??53i Collected Papers in Avian Paleontology Honoring the 90th Birthday of Alexander Wetmore STORRS L. OLSON EDITOR SMITHSONIAN CONTRIBUTIONS TO PALEOBIOLOGY S E R I A L P U B L I C A T I O N S O F T H E S M I T H S O N I A N I N S T I T U T I O N The emphasis upon publications as a means of diffusing knowledge was expressed by the first Secretary of the Smithsonian Institution. In his formal plan for the Insti? tution, Joseph Henry articulated a program that included the following statement: "It is proposed to publish a series of reports, giving an account of the new discoveries in science, and of the changes made from year to year in all branches of knowledge." This keynote of basic research has been adhered to over the years in the issuance of thousands of titles in serial publications under the Smithsonian imprint, com? mencing with Smithsonian Contributions to Knowledge in 1848 and continuing with the following active series: Smithsonian Annals of Flight Smithsonian Contributions to Anthropology Smithsonian Contributions to Astrophysics Smithsonian Contributions to Botany Smithsonian Contributions to the Earth Sciences Smithsonian Contributions to Paleobiology Smithsonian Contributions to Zoology Smithsonian Studies in History and Technology In these series, the Institution publishes original articles and monographs dealing with the research and collections of its several museums and offices and of professional colleagues at other institutions of learning. These papers report newly acquired facts, synoptic interpretations of data, or original theory in specialized fields. These pub? lications are distributed by mailing lists to libraries, laboratories, and other interested institutions and specialists throughout the world. Individual copies may be obtained from the Smithsonian Institution Press as long as stocks are available. S. DILLON RIPLEY Secretary Smithsonian Institution S M I T H S O N I A N C O N T R I B U T I O N S T O P A L E O B I O L O G Y ? N U M B E R 27 Collected Papers in Avian Paleontology Honoring the 90th Birthday of Alexander Wetmore Storrs L. Olson EDITOR ISSUED MAY 2 i 1976 SMITHSONIAN INSTITUTION PRESS City of Washington 1976 A B S T R A C T Olson, Storrs L., editor. Collected Papers in Avian Paleontology Honoring the 90th Birthday of Alexander Wetmore. Smithsonian Contributions to Paleobiology, number 27, 211 pages, 91 figures, 38 tables, 1976.?Eighteen papers covering diverse aspects of avian paleontology?from the earliest known bird to extinct species found in Indian middens?are collected here to honor the 90th birthday of Alexander Wetmore. These are preceded by an appraisal of the current state of avian paleontology and of Alexander Wetmore's influence on it, including a bibliography of his publications in this field. John H. Ostrom analyzes the hypothetical steps in the origin of flight between Archaeopteryx and modern birds. Philip D. Gingerich confirms that Ichthyornis and Hesperornis did indeed bear teeth, that the palate in Hesperornis is paleognathous, and that these Cretaceous toothed birds appear to occupy a position intermediate between dinosaurs and modern birds. Larry D. Martin and James Tate, Jr. describe the skeleton of the Cretaceous diving bird Baptornis advenus and conclude that the Baptornithidae belong in the Hesperornithiformes, but are less specialized than Hesperornis. Pierce Brodkorb describes the first known Cretaceous land bird as forming a new order possibly ancestral to the Coraciiformes and Piciformes. E. N. Kurochkin summarizes the distribution and paleoecology of the Paleogene birds of Asia, with particular emphasis on the evolution of the gruiform families Eogruidae and Ergilornithidae. Pat Vickers Rich and David J. Bohaska describe the earliest known owl from Paleocene deposits in Colorado. Alan Feduccia transfers the Eocene genus Neanis from the Passeriformes to the Piciformes and he and Larry D. Martin go on to refer this and four other genera to a new family of Piciformes, concluding that these were the dominant perching land birds of the Eocene of North America. Storrs L. Olson describes a new species of Todidae from the Oligocene of Wyoming and refers the genus Protornis from the Oligocene of Switzerland to the Momotidae, concluding that the New World Coraciiformes originated in the Old World. Charles T. Collins describes two new species of the Eo-Oligocene genus Aegialornis and presents evidence that the Aegialornithidae should be referred to the Caprimulgiformes rather than to the Apodiformes, although they might be ancestral to the swifts. In the following paper he shows that the earliest known true swifts (Apodidae) are three nominal forms from the Lower Miocene of France which prove to be but a single species of Cypseloides, a modern genus belonging to a primitive sub? family now restricted to the New World. Stuart L. Warter describes a new osprey from the Miocene of California to provide the earliest certain occurrence of the family Pandionidae and he treats functional aspects of the evolution of the wing in Pandion. Hildegarde Howard describes a. new species of flightless mancalline auk, also from the Miocene of California, which is temporally and morphologically intermediate between Praemancalla lagunensis and the species of Mancalla. Robert W. Storer analyzes Pleistocene fossils of pied-billed grebes, synonymizing Podilymbus magnus Shufeldt with modern P. podiceps and describing a new species from peninsular Florida. Kenneth E. Campbell, Jr., lists 53 species of birds, including new species of Buteo and Oreopholus, from a Pleistocene deposit in southwestern Ecuador and compares this with a fauna of similar age from northwestern Peru, both of which indicate more humid condi? tions in the past. Oscar Arredondo summarizes aspects of the morphology, evolution, and ecology of the gigantic owls, eagles, and vultures recently discovered in Pleistocene deposits in Cuba. Joel Cracraft analyzes variation in the moas of New Zealand, reduces the number of species recognized to 13, and suggests that several "species pairs" represent examples of sexual size dimorphism. G. Victor Morejohn reports remains of the extinct flightless duck Chendytes lawi, previously known only from Pleistocene deposits, from Indian middens in northern Cali? fornia and concludes that the species became extinct through human agency less than 3800 years ago. OFFICIAL PUBLICATION DATE is handstamped in a limited number of initial copies and is recorded in the Institution's annual report, Smithsonian Year. SI PRESS NUMBER 6137. SERIES COVER DESIGN: The trilobite Phacops rana Green. Library of Congress Cataloging in Publication Data Main entry under title: Collected papers in avian paleontology honoring the 90th birthday of Alexander Wetmore. (Smithsonian contributions to paleobiology ; no. 27) CONTENTS: Ostrom, J. H. Some hypothetical anatomical stages in the evolution of avian flight? Gingerich, P. D. Evolutionary significance of the Mesozoic toothed birds.?Martin, L. D. and Tate, J., Jr. The skeleton of Baptornis advenus (Aves: Hesperornithiformes). [etc.] Supt. of Docs. No.: SI 1.30:27 1. Birds, Fossil?Addresses, essays, lectures. I. Wetmore, Alexander, 1886- II. Olson, Storrs L. III. Series: Smithsonian Institution. Smithsonian contributions to paleobiology ; no. 27. QE701.S56 no. 27 [QE871] 560'8s [568'.2] 75-619322 Contents Page PREFACE v APPRECIATIONS, by S. Dillon Ripley and Jean Delacour . . . . . . . vii ALEXANDER WETMORE AND THE STUDY OF FOSSIL BIRDS, by Storrs L. Olson xi PUBLICATIONS IN AVIAN PALEONTOLOGY BY ALEXANDER WETMORE xvii INDEX TO FOSSIL AVIAN TAXA DESCRIBED BY ALEXANDER WETMORE . . . . xxv SOME HYPOTHETICAL ANATOMICAL STAGES IN THE EVOLUTION OF AVIAN FLIGHT, by John H. Ostrom 1 EVOLUTIONARY SIGNIFICANCE OF THE MESOZOIC TOOTHED BIRDS, by Philip D. Gingerich 23 T H E SKELETON OF Baptornis advenus (AVES: HESPERORNITHIFORMES), by Larry D. Martin and James Tate, Jr. . . . . . 35 DISCOVERY OF A CRETACEOUS BIRD, APPARENTLY ANCESTRAL TO THE ORDERS CORACIIFORMES AND PICIFORMES (AVES: CARINATAE), by Pierce Brodkorb 67 A SURVEY OF THE PALEOGENE BIRDS OF ASIA, by E. N. Kurochkin 75 T H E WORLD'S OLDEST O W L : A N E W STRIGIFORM FROM THE PALEOCENE OF SOUTHWESTERN COLORADO, by Pat Vickers Rich and David J. Bohaska 87 Neanis schucherti RESTUDIED: ANOTHER EOCENE PICIFORM BIRD, by Alan Feduccia 95 T H E EOCENE ZYGODACTYL BIRDS OF NORTH AMERICA (AVES: PICIFORMES), by Alan Feduccia and Larry D. Martin 101 OLIGOCENE FOSSILS BEARING ON THE ORIGINS OF THE TODIDAE AND THE MOMOTIDAE (AVES: CORACIIFORMES), by Storrs L. Olson . . . . . . . I l l T w o N E W SPECIES OF Aegialornis FROM FRANCE, WITH COMMENTS ON THE ORDINAL AFFINITIES OF THE AEGIALORNITHIDAE, by Charles T . Collins 121 A REVIEW OF THE LOWER MIOCENE SWIFTS (AVES: APODIDAE), by Charles T . Collins 129 A N E W OSPREY FROM THE MIOCENE OF CALIFORNIA (FALCONIFORMES: PANDIONIDAE), by Stuart L. Warter 133 A N E W SPECIES OF FLIGHTLESS AUK FROM THE MIOCENE OF CALIFORNIA (ALCIDAE: MANCALLINAE), by Hildegarde Howard 141 T H E PLEISTOCENE PIED-BILLED GREBES (AVES: PODICIPEDIDAE), by Robert W. Storer 147 T H E LATE PLEISTOCENE AVIFAUNA OF L A CAROLINA, SOUTHWESTERN ECUADOR, by Kenneth E. Campbell, Jr. . . . 155 T H E GREAT PREDATORY BIRDS OF THE PLEISTOCENE OF CUBA, by Oscar Arredondo, translated and amended by Storrs L. Olson 169 T H E SPECIES OF MOAS (AVES: DINORNITHIDAE), by Joel Cracraft 189 EVIDENCE OF THE SURVIVAL TO RECENT T I M E S OF THE EXTINCT FLIGHTLESS DUCK Chendytes lawi MILLER, by G. Victor Morejohn 207 i n Preface Had contributions for this volume been sought from the associates and friends of Alexander Wetmore in all fields of ornithology, their number would have been much too great to permit the timely appearance of this festschrift, for the endeavor was conceived barely in time for its proper execution. It was decided, therefore, to limit the scope of this work to avian paleontology?a study which has been particularly dear to Alex Wetmore for three score years. T h a t this collec? tion could be assembled and set before the press in less than a year is a tribute not only to the eagerness of the contributors to honor their esteemed colleague in his 90th year, but also to the fact that there is currently an extensive and active interest in the study of fossil birds?a fact that must be particularly grati? fying to Dr. Wetmore, who for so many years strived to keep such an interest alive. T h e editor is particularly indebted to Dorsey Dunn and Joanne Williams, who typed and retyped manuscripts with great patience and care, and Anne Curtis, who assisted in preparing numerous illustrations. He also wishes to express his appreciation for the fine cooperation of the contributors; their combined efforts have here produced what is certain to be a landmark in paleornithology. Alexander Wetmore Appreciations S. Dillon Ripley SECRETARY, SMITHSONIAN INSTITUTION Alexander Wetmore is so familiar a figure to scientists as the dean of American ornithology that it is difficult to realize that he has been directly associated with the Smithsonian Institution as an administrator since 1924. His first responsi? bilities were in connection with the National Zoological Park, of which he became Superintendent in 1924. Subsequently, Dr. Wetmore became Assistant Secretary for Science of the Institution and Director of the Museum of Natural History in 1925, and continued as Assistant Secretary until 1945, when he was elected by the Regents to serve as the sixth Secretary, succeeding Dr. Charles G. Abbot, who retired in that year. Throughout this period, and after his own retirement from administrative responsibilities in 1952, Dr. Wetmore has continued an extraordinarily active career in ornithology. In addition to his many duties with the Smithsonian, he also served as Home Secretary of the National Academy of Sciences from 1951 to 1955 and has been for many years a Trustee and Vice-Chairman of the Research Committee of the National Geographic Society. Throughout this career his publications on birds have continued in depth and in great volume. Following his retirement he has continued his monographic studies on the birds of Panama, which have culminated in the publication of three volumes of "The Birds of the Republic of Panama" (Smithsonian Miscel? laneous Collections, volume 150), with a fourth part in preparation. Even now, Dr. Wetmore's work is not completed and he continues to be a productive scien? tist in the laboratory of the Division of Birds. In addition to the many research publications on fossil material specializing in birds, Dr. Wetmore is known today as one of the most outstanding systematic specialists. His renowned arrangement of the sequence of higher taxa of birds, "A Classification for the Birds of the World" (Smithsonian Miscellaneous Col? lections, 139 (ll):l-37, 1960), still stands virtually unchallenged. He is a winner of the Brewster Medal of the American Ornithologists' Union, and recently, in May 1975, of the Hubbard Medal of the National Geographic Society. The amount of materials contributed by him to the collections of the National Museum is monumental. Indeed, present-day ornithologists would be staggered to think of the production of research and study material deposited by Dr. Wet? more in the National Collection: some 26,058 skins from North America, Puerto Rico, Hispaniola, the Hawaiian Islands, Uruguay, Paraguay, Argentina, Chile, Venezuela, and Central America, with more than half, some 14,291, from Panama alone. Of skeletal and anatomical specimens, Dr. Wetmore has prepared and contributed 4363, an enormously important increment to the anatomy collections in Washington. The majority of these are from North America and Puerto Rico, but nearly 1000 are from Central and South America and 540 from Panama vii SMITHSONIAN CONTRIBUTIONS TO PALEOBIOLOGY alone. Of eggs, Dr. Wetmore has collected 201 clutches from North, Central, and South America. In this day and age when the collecting of birds has become markedly diminished due to the general knowledge of specimens in existing museums, as well as the varying directions taken in present-day studies in environ? ment and ecology which tend to preclude such collecting, Dr. Wetmore's collec? tions seem large in retrospect; but they form part of the fundamental resource on which present and future work will depend. The very magnitude of these collections would tend to make further collecting in most areas where he has worked superfluous. So today the specialist in taxonomic studies can be grateful for the efforts of meticulous collectors such as Dr. Wetmore, whose work has laid out in depth representative material. Thus, only highly specific additional col? lecting need be done in the future in areas where Wetmore's work has given us the foundation of our knowledge. The number of species and subspecies described by Dr. Wetmore is equally impressive. Over the years since 1914 he has described as new to science some 189 species and subspecies of recent birds. Many of these, in fact most, are from Central and northern South America, but much of Dr. Wetmore's most signifi? cant early field work was done in the Caribbean, particularly in Puerto Rico, Hispaniola, and adjacent islands in the Greater Antilles. In addition, through the initiative of the late Dr. Casey Wood, Wetmore worked on and described a number of species from the Fiji Islands, as well as forms from other islands of the Pacific. His monographic revisions of a number of species of northern Central and North American birds, as well as Argentinian and southern South American birds, have produced many novelties for science. A great deal of his work was done in revising the avifauna of Venezuela with the late W. H. Phelps, Sr., with whom he co-authored a number of new species and subspecies. At least one of Dr. Wetmore's discoveries, the population of Chilean Pintail found in the vicinity of Bogota, Colombia, has subsequently gone extinct, due presumably to hunting pressure. Many of the environments in which he worked in Colombia and adjacent parts of northern South America are already so radically changed that one wonders whether additional forms may not have gone extinct as well. It is a sadness of our time that the development of tropical regions of the world, with the consequent destruction of forests and unique habitats, par? ticularly in South and Central America, has been so rapid that many forms of the accompanying avifauna may never be seen again in life. In a spirit of pre? science, Alexander Wetmore was an early supporter of the Pan-American Section of the International Council for Bird Preservation, having joined T . Gilbert Pearson, Robert Cushman Murphy, Marshall McLean, William Vogt, and Hoyes Lloyd in helping to set up the original organization with Latin American colleagues. Many of his admirers have named numbers of new birds after our beloved former Secretary, among them a long-billed rail of the Venezuelan coast, Rallus wetmorei, which I have recently considered in my own ornithological work. Including Rallus wetmorei, some 16 modern species and subspecies of birds have been named in honor of Alexander Wetmore, as well as 4 mammals, 7 reptiles and amphibians. 2 fishes, 9 insects, 5 molluscs, a sponge, a cactus, a glacier, and a canopy bridge in the Bayano River forest in Panama. Truly the incessant and intensive zeal which he has single-mindedly given to the study of birds over the years, often at very considerable personal expenditure in time and energy, will mark the career of Alexander Wetmore as one of the most memorable in the entire history of American ornithology. NUMBER 27 IX Jean Delacour DIRECTOR EMERITUS, NATURAL HISTORY MUSEUM OF LOS ANGELES COUNTY I had been corresponding with Alexander Wetmore for several years before I had a chance to meet him. This I did in Washington, D.C., in the spring of 1926. Referring to a visit I made to the National Zoological Park at that time, I wrote as follows: . . . the National Zoological Park is managed by the Assistant Secretary of the Smithsonian Institution, Dr. Alexander Wetmore, one of the youngest and most accomplished naturalists in the United States. Notwithstanding his heavy administrative obligations, Dr. Wetmore finds enough time for study in descriptive ornithology and technical work, and observations of birds in freedom and in captivity, all with remarkable results. I visited the Zoo under his kind guidance. . . . (L'Oiseau, 7(1926):205). Dr. Wetmore himself published in the same issue of that periodical (pages 324-325), a report of the first breeding in captivity at the National Zoo of the Blue Snow Goose, with several photographic plates. He was, therefore, awarded a special medal by the Societe" Nationale d'Acclimatation de France. Dr. Wetmore was Director of the National Zoo for two years, and before he exchanged that function for the Assistant Secretaryship he was responsible for choosing as his successor, Dr. William Mann, who was an outstanding Zoo director for many years. T h e welcome given me by Dr. Wetmore in 1926 remains vivid in my memory, and my mother and I visited Washington under his cordial and competent guidance. Later on, we had many opportunities of getting together at meetings and congresses, as we have had many interests in common. We met in Europe and in America frequently, working together for bird preservation since the inception of the International Council for Bird Preservation. We saw even more of each other after 1940, when I came to live in the United States. We are now among the few ornithologists of our generation still alive. We sadly miss many of our old friends, particularly Frank Chapman, T o m Barbour, Robert Cushman Murphy, James Chapin and T . Gilbert Pearson, to list only a few who worked with us on different projects. It is to me a very special comfort to know that Alex still is here, looking and acting and writing much as he always has, and I wish him all the happiness he deserves. As past Secretary of the Smithsonian Institution he joins the ranks of those others who have seemed over the years almost immortal; thus his continuing research for many years seems assured. Alexander Wetmore and the Study of Fossil Birds Storrs L. Olson In most general discussions of paleontology or ornithology, the subject of fossil birds is almost invariably treated with a predictable uniformity. Mention is made of Archaeopteryx and the Cretaceous toothed birds, and occasionally some of the large Tertiary predators like Diatryma and Phorusrhacos. This is accom? panied by a statement explaining that bird bones are fragile and seldom pre? served, thus accounting for what is alleged to be a meager and uninformative fossil record for the entire class. Through frequent repetition, this myth has gained such general acceptance that the uninformed find it difficult to conceive of an avian paleontologist being able to find enough to keep himself occupied. Yet for 60 years Alexander Wetmore has produced a steady stream of papers on fossil birds. With over 150 such entries and nearly as many new fossil taxa to his credit, he can without reservation be said to have contributed more to this field than any other single person. One cannot help but be humbled to think that this is but a fraction of his total scientific output. Bringing together this collection of papers in avian paleontology to honor Alexander Wetmore's 90th birthday on 18 June 1976 provides not only an opportunity to review his influence on paleornithology over the past six decades, but also offers a chance to begin dispelling the fiction that fossil birds are rare and provide little information on avian evolution. Wetmore's most intensive work on fossil birds took place in the period after the waning of excitement over the spectacular 19th century discoveries of Mesozoic birds, but before most of the renewed modern interest in avian paleontology had been sparked. For many years Wetmore was virtually the only person anywhere who was engaged in research on fossil birds, with the notable exception of the California school of Loye and Alden Miller and Hildegarde Howard. Thus it was natural that bird fossils from all parts of the United States and from areas of the world as diverse as Inner Mongolia, Java, St. Helena, Hawaii, and Ber? muda, passed through Wetmore's hands continually. T o this day, the cabinets in his office hold a rich trove of undescribed treasures from a wide array of horizons and localities. For many years, Wetmore has assiduously maintained an extensive card catalog of references from which he prepared three separate editions of a checklist of fossil birds of North America. He also endeavored to keep his colleagues abreast of current developments in avian paleontology through numerous addresses, lectures, and entertaining synoptic papers?all the while maintaining a consis? tently high level of production of basic detailed descriptions and diagnoses of new forms. Wetmore's first paper on fossil birds involved removing the large Miocene bird described by R. W. Shufeldt as Palaeochenoides miocaenus from the Anseriformes to the Pelecaniformes. Shufeldt, whom Wetmore knew well, was in no way SMITHSONIAN CONTRIBUTIONS TO PALEOBIOLOGY pleased by this, but Wetmore's action was quite correct. Specimens possibly representing two new species of Palaeochenoides have recently come to the National Museum and it now appears that these may provide a breakthrough in our understanding of these huge, enigmatic seabirds. Wetmore's recognition of the true affinities of Palaeochenoides marked the first step toward this under? standing. Shufeldt, it might be noted, was a singular eccentric who, although making many contributions to avian paleontology, repeatedly made serious errors in identification. The process of re-evaluating Shufeldt's taxa, begun by Wetmore and others, has continued tip to the present, as seen, for example, in the papers on Eocene Piciformes elsewhere in this volume. The first new bird Wetmore described from osteological remains was a new genus and species of large flightless rail, Nesotrochis debooyi, found in Indian middens in the Virgin Islands. Tha t such deposits may still be of interest to avian paleontologists is clearly demonstrated by Morejohn in the final paper of the present volume. In recent years two new species of Nesotrochis have been described from Cuba and Hispaniola; despite this, the genus remains so distinc? tive that there is not yet a good clue as to its affinities within the Rallidae. Wetmore continued to draw notice to the extinct Pleistocene birds of the West Indies, analyzing fossil avifaunas from Puerto Rico, Haiti, Cuba, and the Bahamas. Among the most notable of his discoveries was the giant barn owl, Tyto ostologa, of Haiti, which he correctly diagnosed from a small fragment of tarsometatarsus. He later described a similar species, T. pollens, along with two new large eagles, from the Bahamas. As late as 1959, Brodkorb, in dedicating to him a new fossil species of crow from New Providence Island, remarked that Alexander Wetmore was "responsible for all previous knowledge of fossil birds of the West Indies." Since then, there have been many additional discoveries of avian fossils in the Antilles, the most remarkable of which are certainly the gigantic raptors of Cuba brought to light through the labors of Oscar Arredondo (summarized in this volume). Among the material from the same deposits that yielded Tyto ostologa, a new rail and a new falcon have recently been found. There is every reason to believe that the fossil resources of the Greater Antilles will continue to produce surprises, while as far as avian paleontology is con? cerned, the Lesser Antilles are terra incognita. Perhaps the greatest proportion of Wetmore's paleontological efforts concerned the identification and description of Tertiary birds from North America, espe? cially those of the Eocene, Oligocene, and Miocene terrestrial deposits of the western states and the marine Miocene of the east coast. In these areas he has laid the groundwork for all future researches. Some of the most exciting recent finds of fossil birds are from the extensive lower Eocene deposits of the Green River Formation, for these often yield com? plete, articulated skeletons, as for example a particularly fine specimen of primi? tive frigatebird now under study by the writer. Feduccia and Martin in this volume discuss the significance of the Green River Piciformes, which are now coming to light with remarkable rapidity since Brodkorb's recognition of the first species in 1970. But perhaps the most astonishing of developments in Green River paleornithology are the tremendous deposits of flamingo bones discovered by Paul O. McGrew and now under study by him and Alan Feduccia. Here too, Wetmore's past contributions have played a part, for he described this flamingo in 1926 as a new genus of recurvirostrid, Presbyornis. This case of mistaken identity is understandable in view of Feduccia's further investigations, which NUMBER 27 x u 4 have disclosed some extraordinary similarities between the skeletons of recurvi- rostrids and flamingos, particularly those of the lower Eocene forms. This is further confirmed by an undescribed flamingo of Bridgerian age in the National Museum which is even more similar to recurvirostrids than is Presbyornis. These discoveries now appear to be leading to a reappraisal of the affinities of both the flamingos and the shorebirds. Wetmore's several contributions on Eocene owls resulted in his erecting a new family, the Protostrigidae, the importance of which is only now becoming apparent. T h e fossil record of owls is particularly good and we now know that the order extends back at least as far as the Paleocene (see Rich and Bohaska's paper in this volume). Much unstudied material of fossil owls is to be found in various museums, which, along with the revision of the many forms already known, should provide an especially fruitful area of inquiry for avian paleon? tologists in the future. Of Wetmore's Eocene birds, perhaps the most provocative is Neocathartes grallator, a long-legged vulture that was based on a nearly complete skeleton. Wetmore's contributions once provided just about all that was known of the birds from the extensive Oligocene deposits of western North America. These are now producing new and extremely interesting fossil birds almost annually (e.g., Olson's paper in this volume). One of the predominant groups of birds in the North American Oligocene was the gruiform family that Wetmore named the Bathornithidae. Wetmore himself offered more than one interpretation of the possible relationships of this group and Cracraft has recently proposed others. It seems certain that the final word has not been said on this matter, but the importance of the Bathornithidae is undisputed. Once again, it was Wetmore's pioneering work on the group that has made possible all subsequent investiga? tions. It now appears that the Oligocene limpkins (Aramidae) described by Wetmore will soon be augmented by a new genus, known from much of a skeleton collected in Wyoming by Dr. R. J. Emry of the National Museum. Oligocene raptors described by Wetmore include two forms inseparable from the modern genus Buteo, and an intriguing species, Palaeoplancus sternbergi, which was made the type of a new subfamily of Accipitridae. For Wetmore, some of the most interesting fossil deposits were those closest to home?the Miocene marine beds of the Chesapeake Group. Most of what we know of the birds of these deposits is to be found in Wetmore's publications, including the description of a diminutive gannet, Microsula avita, which is now known to be relatively common in these beds. In the past few years many new specimens, some of them highly significant, have come to the National Museum from this area, although these are as yet undescribed. As abundant as this material is, it is far overshadowed by the tremendous collections of Miocene and Pliocene age that have recently been acquired from a phosphate mine in North Carolina and which this writer has had the privilege of studying in collaboration with Dr. Wetmore. This is probably the largest deposit of Tertiary birds in existence and thousands of fossils of more than 50 species have so far been recovered. These collections, along with those from Bone Valley, Florida, being studied by Brodkorb, and those from the Pacific coast, which are constantly productive (see the contributions by Howard and Warter in this volume), provide a solid basis for making unprecedented gains in our knowledge of evolution in the Alcidae, Procellariidae, Diomedeidae, Gaviidae, Sulidae, Phalacrocoracidae, and other families of marine birds. SMITHSONIAN CONTRIBUTIONS TO PALEOBIOLOGY Dr. Wetmore on a Smithsonian collecting trip to the Lee Creek phosphate mine, Aurora, North Carolina, 26 April 1972. In 1931, Wetmore published a large paper on the Pleistocene avifauna of Florida in which it was shown that several birds, such as the California condor and the huge vulture Teratornis, then known only from the west, particularly from the tarpits at Rancho la Brea, were also present in Florida. This opened up a very fertile area of investigation and in succeeding years the studies of Brodkorb and others have continued to be a source of new information on the rich Pleistocene avifauna of Florida (e.g., Storer's paper herein). In his many years of involvement in paleornithology, Wetmore has repeatedly been called upon to identify material from Pleistocene caves and from Indian middens, a task which as often as not holds few rewards but which nevertheless he pursued with alacrity. From such studies he published numerous notes showing that the distribution of many modern North American species was once much different than at present, as indicated, for example, by Canada Jays, Magpies, and Sharp- tailed Grouse in Virginia, and Spruce Grouse in Virginia and Georgia. The sum of these observations has proved to be a significant contribution to our knowledge of the effects of Pleistocene climatic changes on avian distribution. When the Central Asiatic Expeditions of the American Museum of Natural History discovered fossil birds in the Eocene of Inner Mongolia, it was to Wet? more that the specimens were sent for study. The most abundant material was that of the crane-like bird which Wetmore named Eogrus aeola, assigning it to NUMBER 27 XV a new family, Eogruidae. Recently, the significance of these birds as the probable ancestors of the peculiar two-toed running birds of the family Ergilornithidae has been demonstrated (see Kurochkin's paper herein) and provides one of the most interesting examples of an evolutionary lineage in the avian fossil record. Oceanic islands are of particular interest to the avian paleontologist because of the rapid extinction of species after the introduction of exotic predators by man. Most such introductions occurred before the era of scientific exploration and thus many insular species can be known only from the study of fossil or subfossil remains. Here Wetmore has likewise made numerous contributions. In 1943 he described an extinct goose from the island of Hawaii. This turned out to be but a small indication of what was to come, for in the past few years the Bishop Museum has forwarded to him for examination numerous fossils from Molokai and Maui, which comprise one of the most extraordinary avifaunas ever uncovered, some of the species being so anomalous as to be quite beyond the wildest imaginations of the most whimsical fantasizer. From Pleistocene deposits on Bermuda, Wetmore described a crane and a duck, leaving to Brod? korb the naming of five new rails from these and other deposits on the island (as yet undescribed). From St. Helena, in the South Atlantic Ocean, Wetmore named a new rail to provide a first step in the elucidation of the extensive fossil avifauna of that island, which this writer has recently had the opportunity to expand. We have touched on but a few of Alexander Wetmore's contributions to avian paleontology and their importance to present and future research. It should by now be clear that, contrary to persistent belief, fossil birds are not uncommon, and in the following pages it should be equally evident that there is much to be gained from their study. At last there is some light being shed on the study of Cretaceous land birds (see Brodkorb's paper herein), an area that had hitherto been a void. T h e renowned Pleistocene tarpits at Rancho la Brea, California, long erroneously held to be the only really productive source of avian fossils, now find a rival in similar deposits in South America which portend a new era of discovery on that continent (see Campbell's paper in the present volume). Although these many new finds are of paramount importance, the avian paleontologist has also inherited a rich source of information in the fossils that have been made known previously. Re-examination of the much discussed but widely misunderstood Mesozoic birds, such as the Jurassic Archaeopteryx and the Cretaceous toothed divers, has generated exciting new ideas and controversy, all of which can only lead to a better understanding of avian evolution (see the papers by Ostrom, Gingerich, and Martin and Tate in this volume). Long-neglected fossil birds, such as those from the vast Tertiary collections of France and from the wealth of material in the New Zealand Quaternary, are coming under scrutiny once again, and in the light of modern concepts find a better place in the evolutionary scheme (see papers herein by Collins and Cracraft). It would seem, therefore, that avian paleontology is truly experiencing a renaissance. In 1932, Joseph Grinnell (Auk, 49:9-13) in pondering the latest edition of the American Ornithologists' Union's Checklist of North American Birds, to which Wetmore contributed the portion on fossils, attempted to make some inferences about future lists and the number of species they might contain. Concerning the fossil list he queried, "And what about the number and relative acumen of future students in avian paleontology: Will they be more numerous and more XVi SMITHSONIAN CONTRIBUTIONS TO PALEOBIOLOGY alert than heretofore or will the attractions in this field wane in the face of the ascending allurements for bright minds of bio-physics, bio-chemistry and cosmic mathematics? These questions are more or less baffling of answer." Forty-five years later, the answers are apparent. We offer the present volume as testimony to the fact that avian paleontology has quite enough allure of its own to attract numerous and perspicacious practitioners, and that the materials they study allow of significant advances not only in the knowledge of birds, but of biology and paleontology as a whole. The discipline that Alexander Wetmore nurtured for sixty years is expanding and vigorous and reaping the benefits of his devotion. Publications in Avian Paleontology by Alexander Wetmore 1917 1. The Relationships of the Fossil Bird Palaeochenoides miocaenus. Journal of Geology, 25(6): 555-557, 1 figure. 1918 2. Bones of Birds Collected by Theodoor de Booy from Kitchen Midden Deposits in the Islands of St. Thomas and St. Croix. Proceedings of the United States National Museum, 54(2245):513-522, plate 82. (21 November)1 1920 3. Five New Species of Birds from Cave Deposits in Porto Rico. Proceedings of the Biological Society of Washington, 33:77-82, plates 2-3. (30 December) 1922 4. A Fossil Owl from the Bridger Eocene. Proceedings of the Academy of Natural Sciences of Philadelphia, 73(3):455^58, 2 figures. (6 April) 5. Bird Remains from the Caves of Porto Rico. Bulletin of the American Museum of Natural History, 46(4):297-333, 25 figures. 6. Remains of Birds from Caves in the Republic of Haiti. Smithsonian Miscellaneous Collec? tions, 74(4): 1-4, 2 figures. (17 October) 1923 7. An Additional Record for the Extinct Porto Rican Quail-Dove. Auk, 40(2):324. 8. Avian Fossils from the Miocene and Pliocene of Nebraska. Bulletin of the American Museum of Natural History, 48(12):483-507, 20 figures. (3 December) 1924 9. Fossil Birds from Southeastern Arizona. Proceedings of the United States National Museum, 64(5): 1-18, 9 figures. (15 January) 1925 10. The Systematic Position of Palaeospiza bella Allen, with Observations on Other Fossil Birds. Bulletin of the Museum of Comparative Zoology, 67(2): 183-193, 4 figures, plates 1-4. (May) 11. Another Record for the Genus Corvus in St. Croix. Auk, 42(3):446. 1926 12. Descriptions of Additional Fossil Birds from the Miocene of Nebraska. American Museum Novitates, 211:1-5, 6 figures. (11 March) 13. Fossil Birds from the Green River Deposits of Eastern Utah. Annals of the Carnegie Mu? seum, 16(3-4):391-402, plates 36-37. (10 April) 1 Exact dates of publication, when known, are included for papers in which new taxa are proposed. X V l l SMITHSONIAN CONTRIBUTIONS TO PALEOBIOLOGY 14. Description of a Fossil Hawk from the Miocene of Nebraska. Annals of the Carnegie Museum, 16(3-4):403-408, plate 38. (10 April) 15. Observations on Fossil Birds Described from the Miocene of Maryland. Auk, 43(4):462-468. 16. The Fossil Birds of North America. Natural History, 26(5):525-526. 17. [Abstract of] A. Wetmore, Descriptions of Additional Fossil Birds from the Miocene of Nebraska. Biological Abstracts, 1(1):201. 18. An Additional Record for the Fossil Hawk Urubitinga enecta. American Museum Novitates, 241:1-3, 3 figures. 1927 19. Present Status of the Check-list of Fossil Birds for North America. Auk, 44(2): 179-183. 20. Fossil Birds from the Oligocene of Colorado. Proceedings of the Colorado Museum of Natural History, 7(2): 1-13, 23 figures. (15 July) 21. [On Cygnus paloregonus from Nampa, Idaho.] Page 267 in O. P. Hay, The Pleistocene of the Western Region of North America and Its Vertebrated Animals. Carnegie Institution of Washington Publication, 322B. 22. A Record of the Ruffed Grouse from the Pleistocene of Maryland. Auk, 44(4):561. 23. The Birds of Porto Rico and the Virgin Islands: Colymbiformes to Columbiformes. Pages 245-406 of part 3 in volume 9 of New York Academy of Sciences, Scientific Survey of Porto Rico and the Virgin Islands. 1 map, 16 figures, plates 55-61. The Birds of Porto Rico and the Virgin Islands: Psittaciformes to Passeriformes. Pages 407-598 of part 4 in volume 9 of New York Academy of Sciences, Scientific Survey of Porto Rico and the Virgin Islands. 3 figures, plates 62-65. [Includes discussion and figures of fossil species.] 1928 24. Bones of Birds from the Ciego Montero Deposit of Cuba. American Museum Novitates, 301:1-5, 2 figures. 25. Additional Specimens of Fossil Birds from the Upper Tertiary Deposits of Nebraska. American Museum Novitates, 302:1-5, 2 figures. 26. The Tibio-tarsus of the Fossil Hawk Buteo typhoius. Condor, 30(2): 149-150, figures 58-61. 27. The Systematic Position of the Fossil Bird Cyphornis magnus. (Contributions to Canadian Palaeontology, Geological Series Number 48). Canada Department of Mines, Geological Survey Bulletin, 49:1-4, 1 figure. (15 March) 28. Prehistoric Ornithology in North America. Journal of the Washington Academy of Sciences, 18(6): 145-158. 29. The Short-tailed Albatross in Oregon. Condor, 30(3): 191. 30. [List of Aves.] Page 3 in G. G. Simpson, Pleistocene Mammals from a Cave in Citrus County, Florida. American Museum Novitates, 328. 1929 31. [Abstract of] J. F. van Bemmelen, Animaux disparus. Biological Abstracts, 3(l-3):390. 32. [Abstract of] W. v. Szeliga-Mierzeyewski, Der diluviale Kernbeisser (Loxia coccothraustes L.) aus Starunia in Polen (Anatomie und Histologic). Biological Abstracts, 3(1-3): 1012. 33. Birds of the Past in North America. Pages 377-389 in Smithsonian Report for 1928. 11 plates. Washington, Government Printing Office. 1930 34. The Fossil Birds of the A. O. U. Check-list. Condor, 32(1): 12-14, 1 table. 35. [and H. T. Martin.] A Fossil Crane from the Pliocene of Kansas. Condor, 32(l):62-63, figures 23-25. (20 January) 36. [Abstract of] G. Archey. On a Moa Skeleton from Amodes Bay and some Moa Bones from Karamu. Biological Abstracts, 4(l):287-288. 37. The Age of the Supposed Cretaceous Birds from New Jersey. Auk, 47(2): 186-188. 38. [Abstract of] M. D. d. Saez, Las Aves Corredoras F6siles del Santacru Cense [sic]. Biological Abstracts, 4(3):992. NUMBER 27 XIX 39. Two Fossil Birds from the Miocene of Nebraska. Condor, 32(3): 152-154, figures 51-56. (15 May) 40. Fossil Bird Remains from the Temblor Formation near Bakersfield, California. Proceedings of the California Academy of Sciences, series 4, 19(8):85-93, 7 figures. (15 July) 41. The Supposed Plumage of the Eocene Diatryma. Auk, 47(4):579-580. 1931 42. [and B. H. Swales.] The Birds of Haiti and the Dominican Republic. United States Na? tional Museum Bulletin, 155:1^83, 2 figures, 26 plates. [Includes discussion of fossils.] 43. The California Condor in New Mexico. Condor, 33(2):76-77. 44. The Avifauna of the Pleistocene in Florida. Smithsonian Miscellaneous Collections, 85(2): 1-41, 16 figures, 6 plates. (13 April) 45. Two Primitive Rails from the Eocene of Colorado and Wyoming. Condor, 33(3): 107-109, figures 21-29. (15 May) 46. [Report on Birds Found in a Limestone Urn at Chichen Itza.] Page 189 in volume 1 of E. H. Morris, J. Chariot, and A. A. Morris, The Temple of the Warriors at Chichen Itza, Yucatan. Carnegie Institution of Washington Publication, 406. 47. The Pleistocene Avifauna of Florida. Pages 479^183 in Proceedings of the VHth Inter? national Ornithological Congress at Amsterdam 1930. 48. The Fossil Birds of North America. Pages 401^72 in Check-list of North American Birds. Fourth edition. Lancaster, Pennsylvania: American Ornithologists' Union. 49. Bones of the Great Horned Owl from the Carlsbad Cavern. Condor, 33(6):248-249. 50. Record of an Unknown Woodpecker from the Lower Pliocene. Condor, 33(6):255-256. 1932 51. Additional Records of Birds from Cavern Deposits in New Mexico. Condor, 34(3): 141-142. 52. The Former Occurrence of the Mississippi Kite in Ohio. Wilson Bulletin, 44(2): 118. 1933 53. [and H. Friedmann.] The California Condor in Texas. Condor, 35(1): 37-38. 54. A Fossil Gallinaceous Bird from the Lower Miocene of Nebraska. Condor, 35(2):64-65. (17 March) 55. Status of the Genus Geranoaetus. Auk, 50(2):212. 56. A Second Specimen of the Fossil Bird Bathornis veredus. Auk, 50(2):213-214. 57. Fossil Bird Remains from the Eocene of Wyoming. Condor, 35(3): 115?118, figure 22 (15 May) 58. Bird Remains from the Oliocene Deposits of Torrington, Wyoming. Bulletin of the Museum of Comparative Zoology, 75(7):297?311, 19 figures. (October) 59. Development of Our Knowledge of Fossil Birds. Pages 231-239 in Fifty Years' Progress of American Ornithology 1883-1933. Lancaster, Pennsylvania: American Ornithologists' Union. 60. The Status of Minerva antiqua, Aquila ferox, and Aquila lydekkeri as Fossil Birds. Ameri? can Museum Novitates, 680:1^1, 1 figure. (4 December) 61. An Oligocene Eagle from Wyoming. Smithsonian Miscellaneous Collections, 87(19): 1-9, 19 figures. (26 December) 62. Pliocene Bird Remains from Idaho. Smithsonian Miscellaneous Collections, 87(20): 1-12, 8 figures. (27 December) 1934 63. [and E. C. Case.] A New Fossil Hawk from the Oligocene Beds of South Dakota. Contri? butions from the Museum of Paleontology, University of Michigan, 4(8): 129-132, 1 plate. (15 January) 64. A Fossil Quail from Nebraska. Condor, 36(1):30, figure 5. (15 January) 65. [Review of] K. Lambrecht, Handbuch der Palaeornithologie. Auk, 51(2):261-263. 66. Fossil Birds from Mongolia and China. American Museum Novitates, 711:1-16, 6 figures. (7 April) 67. The Types of the Fossil Mammals Described as Aquila antiqua and Aquila ferox. Journal of Mammalogy, 15(3):251. XX SMITHSONIAN CONTRIBUTIONS TO PALEOBIOLOGY 1935 68. On the Genera Oligocorax and Miocorax. Auk, 52(1):75?76. 69. The Mexican Turkey Vulture in the United States. Condor, 37(3): 176. 70. The Common Loon in the Florida Keys. Auk, 52(3):300. 71. Pre-Columbian Bird Remains from Venezuela. Auk, 52(3):328-329. 72. A Record of the Trumpeter Swan from the Late Pleistocene of Illinois. Wilson Bulletin, 47(3):237. 73. Aves (Birds). Pages 275-277 in C. B. Schultz and E. B. Howard, The Fauna of Burnet Cave, Guadalupe Mountains, New Mexico. Proceedings of the Academy of Natural Sciences of Philadelphia, 87:273-298. 1936 74. The Range of the Sharp-tailed Grouse in New Mexico. Condor, 38(2):90. 75. How Old Are Our Birds? Bird-Lore, 38(5):321-326, 7 figures. 76. Two New Species of Hawks from the Miocene of Nebraska. Proceedings of the United States National Museum, 84(3003):73-78, figures 13-14. (3 November) 1937 77. The Eared Grebe and Other Birds from the Pliocene of Kansas. Condor, 39(I):40. 78. Ancient Records of Birds from the Island of St. Croix with Observations on Extinct and Living Birds of Puerto Rico. Journal of Agriculture of the University of Puerto Rico, 21(1):5-16, 1 plate. (January) 79. The Systematic Position of Bubo leptosteus Marsh. Condor, 39(2):84-85, figure 23. 80. Bird Remains from Cave Deposits on Great Exuma Island in the Bahamas. Bulletin of the Museum of Comparative Zoology, 80(12):427-441, 16 figures, 1 plate. (October) 81. The Tibiotarsus of the Fossil Bird Bathornis veredus. Condor, 39(6):256-257, figure 70. 82. A Record of the Fossil Grebe, Colymbus parvus, from the Pliocene of California, with Remarks on Other American Fossils of This Family. Proceedings of the California Acad? emy of Sciences, series 4, 23(13): 195-201, 15 figures. 1938 83. A Miocene Booby and Other Records from the Calvert Formation of Maryland. Proceedings of the United States National Museum, 85(3030):21-25, figures 2-3. (14 January) 84. Another Fossil Owl from the Eocene of Wyoming. Proceedings of the United States Na? tional Museum, 85(3031):27-29, figures 4-5. (17 January) 85. Bird Remains from the West Indies. Auk, 55(1):51?55. 86. A Fossil Duck from the Eocene of Utah. Journal of Paleontology, 12(3):280-283, 5 figures. (4 May) 1939 87. A Pleistocene Egg from Nevada. Condor, 41(3):98-99, figure 29. 88. [On Marsh's Discovery of Toothed Birds.] Page 48 in C. Schuchert, Biographical Memoir of Othniel Charles Marsh. National Academy of Sciences of the United States of America Biographical Memoirs, 20(1): 1-78. 1940 89. Fossil Bird Remains from Tertiary Deposits in the United States. Journal of Morphology, 66(l):25-37, 14 figures. (2 January) 90. A Check-list of the Fossil Birds of North America. Smithsonian Miscellaneous Collections, 99(4): 1-81. 91. Avian Remains from the Pleistocene of Central Java. Journal of Paleontology, 14(5):447- 450, 7 figures. (1 September) 1941 92. An Unknown Loon from the Miocene Fossil Beds of Maryland. Auk, 58(4):567. NUMBER 27 XXi 1942 93. Two New Fossil Birds from the Oligocene of South Dakota. Smithsonian Miscellaneous Collections, 101(14): 1-6, 13 figures. (11 May) 1943 94. Evidence for the Former Occurrence of the Ivory-billed Woodpecker in Ohio. Wilson Bulletin, 55(1):55. 95. Remains of a Swan from the Miocene of Arizona. Condor, 45(3): 120. 96. Fossil Birds from the Tertiary Deposits of Florida. Proceedings of the New England Zoo? logical Club, 32:59-68, plates 11-12. (23 June) 97. The Little Brown Crane in Ohio. Wilson Bulletin, 55(2): 127. 98. The Occurrence of Feather Impressions in the Miocene Deposits of Maryland. Auk, 60(3): 440-441. 99. [Review of] L. Miller and I. DeMay, The Fossil Birds of California. Auk, 60(3):458-459. 100. An Extinct Goose from the Island of Hawaii. Condor, 45(4): 146-148, figure 39. (23 July) 101. A Second Specimen of the Fossil Guillemot, Miocepphus. Auk, 60(4):604. 102. Two More Fossil Hawks from the Miocene of Nebraska. Condor, 45(6):229-231, figures 62-63. (8 December) 1944 103. A New Terrestrial Vulture from the Upper Eocene Deposits of Wyoming. Annals of the Carnegie Museum, 30:57-69, 10 figures, 5 plates. (24 May) 104. Remains of Birds from the Rexroad Fauna of the Upper Pliocene of Kansas. University of Kansas Science Bulletin, 30(pt. 1, no. 9):89-105, 19 figures. (15 May) 1945 105. A Further Record for the Double-crested Cormorant from the Pleistocene of Florida. Auk, 62(3):459. 106. Record of the Turkey from the Pleistocene of Indiana. Wilson Bulletin, 57(3):204. 107. From My Cave Notebooks. Bulletin of the National Speleological Society, 7:1-5. 1948 108. A Pleistocene Record for Mergus merganser in Illinois. Wilson Bulletin, 60(4):240. 1949 109. Archaeopteryx. Pages 260-262 in volume 2 of Encyclopaedia Britannica. 2 figures. 110. Diatryma. Page 324 in volume 7 of Encyclopaedia Britannica. 111. Hesperornis. Pages 530-531 in volume 11 of Encyclopaedia Britannica. 112. Ichthyornis. Page 58A in volume 12 of Encyclopaedia Britannica. 113. Odontornithes. Page 707 in volume 16 of Encyclopaedia Britannica. 114. Phororhacos. Pages 778-779 in volume 17 of Encyclopaedia Britannica. 1 figure. 115. The Pied-billed Grebe in Ancient Deposits in Mexico. Condor, 51(3):150. 1950 116. A Correction in the Generic Name for Eocathartes grallator. Auk, 67(2):235. (28 April) 1951 117. The Original Description of the Fossil Bird Cryptornis antiquus. Condor, 53(3): 153. 118. A Revised Classification for the Birds of the World. Smithsonian Miscellaneous Collec? tions, 117(4): 3. (1 November) XXii SMITHSONIAN CONTRIBUTIONS TO PALEOBIOLOGY 1952 119. Presidential Address. Recent Additions to Our Knowledge of Prehistoric Birds 1933-1949. Pages 51-74 in Proceedings of the Xth International Ornithological Congress Uppsala June 1950. 120. A Record for the Black-capped Petrel, Pterodroma hasitata, in Martinique. Auk, 69(4):460. 1955 121. The Genus Lophodytes in the Pleistocene of Florida. Condor, 57(3): 189. 122. A Supposed Record of a Fossil Cormorant. Condor, 57(6):371. 123. Paleontology. Pages 44-56 in A. Wolfson, editor, Recent Studies in Avian Biology. Urbana: University of Illinois Press. 1956 124. A Check-list of the Fossil and Prehistoric Birds of North America and the West Indies. Smithsonian Miscellaneous Collections, 131(5): 1-105. 125. A Fossil Guan from the Oligocene of South Dakota. Condor, 58(3):234-235, 1 figure. (23 May) 126. Footprint of a Bird from the Miocene of Louisiana. Condor, 58(5):389-390, 1 figure. 127. The Muscovy Duck in the Pleistocene of Panama. Wilson Bulletin, 68(4):327. 1957 128. A Fossil Rail from the Pliocene of Arizona. Condor, 59(4):267-268, 1 figure. (23 July) 1958 129. Miscellaneous Notes on Fossil Birds. Smithsonian Miscellaneous Collections, 135(8):1-11, 5 plates. (26 June) 1959 130. Birds of the Pleistocene in North America. Smithsonian Miscellaneous Collections, 138(4): 1-24. 131. Notes on Certain Grouse of the Pleistocene. Wilson Bulletin, 71(2): 178-182, 1 table, 4 figures. 1960 132. A Classification for the Birds of the World. Smithsonian Miscellaneous Collections, 139(11): 4. (23 June) 133. Pleistocene Birds in Bermuda. Smithsonian Miscellaneous Collections, 140(2): 1-11, 3 plates. 0 July) 134. [and K. C. Parkes.] Archaeornithes. Pages 510-511 in volume 1 of McGraw-Hill Encyclo? pedia of Science and Technology. 135. Aves Fossils. Pages 694-695 in volume 1 of McGraw-Hill Encyclopedia of Science and Technology. 1 figure. 136. [and K. C. Parkes.] Diatrymiformes. Page 104 in volume 4 of McGraw-Hill Encyclopedia of Science and Technology. 1 figure. 137. [and K. C. Parkes.] Dinornithiformes. Page 108 in volume 4 of McGraw-Hill Encyclopedia of Science and Technology. 138. Hesperornis. Pages 426-427 in volume 6 of McGraw-Hill Encyclopedia of Science and Technology. 139. Ichthyornithes. Page 8 in volume 7 of McGraw-Hill Encyclopedia of Science and Tech? nology. NUMBER 27 XX111 1962 140. Notes on Fossil and Subfossil Birds. Smithsonian Miscellaneous Collections, 145(2): 1-17, 2 figures. (26 June) 141. Birds. Pages 92, 95 in J. E. Guilday, The Pleistocene Local Fauna of the Natural Chim? neys, Augusta County, Virginia. Annals of the Carnegie Museum, 36(9):87-122. 142. Ice Age Birds in Virginia. Raven, 33(4):3. 1963 143. An Extinct Rail from the Island of St. Helena. Ibis, 103b(3):379-381, plate 9. (1 Sep? tember) 1964 144. [List of Aves.] Page 134 in J. E. Guilday, P. S. Martin, and A. D. McCrady, New Paris No. 4: A Pleistocene Cave Deposit in Bedford County, Pennsylvania. Bulletin of the National Speleological Society, 26(4): 121-194. 1965 145. [Aves.] Pages 71-72 in volume 1 of L. S. B. Leakey, Olduvai Gorge 1951-61. Cambridge: University Press. 1967 146. Pleistocene Aves from Ladds, Georgia. Bulletin of the Georgia Academy of Science, 25(3): 151-153, 1 figure. 147. Re-creating Madagascar's Giant Extinct Bird. National Geographic, 132(4):488^93, 7 figures. 1968 148. [With C. E. Ray, D. H. Dunkle, and P. Drez.] Fossil Vertebrates from the Marine Pleisto? cene of Southeastern Virginia. Smithsonian Miscellaneous Collections, 153(3): 1-25, 2 figures, 2 plates. 149. Archaeopteryx. Pages 284-285 in volume 2 of Encyclopaedia Britannica, 2 figures. 150. Diatryma. Page 370 in volume 7 of Encyclopaedia Britannica. 151. Hesperornis. Pages 461-462 in volume 11 of Encyclopaedia Britannica. 152. Ichthyornis. Page 1055 in volume 11 of Encyclopaedia Britannica. 153. Phororhacos. Page 911 in volume 17 of Encyclopaedia Britannica. 1 figure. 1972 154. [Review of] G. G. Simpson, A Review of the Pre-Pliocene Penguins of New Zealand. Quarterly Review of Biology, 47(1)78-79. 155. A Pleistocene Record for the White-winged Scoter in Maryland. Auk, 90(4):910-911. Index to Fossil Avian Taxa Described by Alexander Wetmore The status of a number of these taxa has changed since their original descrip? tion and therefore only an alphabetical arrangement is attempted here. Species are listed in the genera in which they were originally described. Taxa marked with an asterisk are preoccupied and no longer available. Following each name is the publication number (from the preceding bibliography) and page in which the name was proposed. SUPERFAMILIES, FAMILIES, AND SUBFAMILIES Bathorn i th idae , 58:301 Ba thorn i th inae , 20:13 Cladorni thes , 132:4 Cyphorni th idae , 27:4 Eleu therorn i th idae , 118:' ?Eoca thar t idae , 103:69 ?Eocathar to idea , 103:69 Eogruidae, 65:30 Aphanocrex, 143:379 Aramornis, 12:1 Badistornis, 89:30 Baeopteryx, 133:6 Bathornis, 20:11 Calohierax, 80:428 *Eocathartes, 103:58 Eocrex, 45:107 Eogrus, 65:3 Eonessa, 85:280 Gaviella, 89:28 Geochen, 100:146 Geranoides, 57:115 Eonessinae, 85:280 Gaviellinae, 89:30 Geranoididae, 57:115 Naut i lo rn i th inae , 13:394 Neocathar t idae, 116:235 Neocathartoidea, 116:235 Palaeoplancinae, 61:4 Palaeospizidae, 10:190 GENERA AND SUBGENERA Gnotornis, 93:1 Microsula, 83:25 Miocepphus, 89:35 Nautilornis, 13:392 Neocathartes, 106:235 Nesotrochis, 2:516 Palaealectoris, 39:152 Palaeastur, 102:230 Palaeocrex, 20:9 Palaeogyps, 20:5 Palaeonossax, 125:234 Palaeoplancus, 61:1 Palaeorallus, 45:108 Palaeotr inginae, 90:57 ?Plegadorni thidae, 140:3 *Plegadornithoidea, 140:3 Presbyorni thidae, 13:396 Protostrigidae, 60:4 Rhegminorn i th idae , 96:60 Telecrecinae, 65:14 Palaeostruthus, 10:192 Paractiornis, 39:153 Phasmagyps, 20:30 *Plegadornis, 140:1 Presbychen, 40:92 Presbyornis, 13:396 Promilio, 129:3 Protostrix, 60:3 Rhegminornis, 96:61 Telecrex, 65:13 Titanohierax, 80:430 abavus, Presbychen, 40:92 aeola, Eogrus, 65:30 ales, Geranoaetus, 14:403 anaticula, Eonessa, 85:280 antecessor, Plegadornis, 140:1 antecursor, Buteo, 58:298 anthonyi, Gallinago, 3:78 aramiellus, Gnotornis, 93:1 aramus, Badistornis, 89:30 atavus, Palaeastur, 102:230 autochthones, Ara, 78:12 avita, Sula, 83:22 SPECIES avus, Nautilornis, 13:392 brodkorbi, Promilio, 129:4 bunkeri, Nettion, 104:92 calobates, Rhegminornis 96:61 cavatica, Tyto, 3:80 celeripes, Bathornis, 58:302 concinna, Gavia, 89:25 conterminus, Geranoaetus, 8:487 contortus, Geranoaetus, 8:492 cooki, Cyrtonyx, 64:30 cursor, Bathornis, 58:310 debooyi, Nesotrochis, 2:516 effera, Proictinia, 8:504 enecta, Urubitinga, 8:500 epileus, Promilio, 129:4 eversa, Dendrocygna, 9:3 fax, Palaeocrex, 20:9 fratercula, Conuropsis, 12:3 geographies, Bathornis, 93:3 gloveralleni, Titanohierax, 79:431 X X V XXVI SMITHSONIAN CONTRIBUTIONS TO PALEOBIOLOGY grallator, Eocathartes, 103:58 grangeri, Buteo, 63:129 grangeri, Telecrex, 65:13 halieus, Pelecanus, 62:3 hesternus, Micropalama, 9:11 hibbardi, Colinus, 104:96 howardae, Palaeoborus, 75:73 inceptor, Puffinus, 40:86 incertus, Palaealectoris, 39:152 jepseni, Geranoides, 57:115 larva, Oreopeleia, 3:79 latebrosus, Polyborus, 3:77 latipes, Baeopteryx, 133:6 longurio, Aramornis, 12:1 mcclungi, Miocepphus, 89:35 micula, Chloroenas, 9:13 mimica, Protostrix, 84:27 minuscula, Branta, 9:6 nannodes, Grus, 35:62 ostologa, Tyto, 6:2 pachyscelus, Anas, 133:2 palaeodytes, Gavia, 96:64 patritus, Phasmagyps, 20:3 perpusillus, Paractiornis, 39:153 pervetus, Presbyornis, 13:396 phengites, Ortalis, 8:487 phillipsi, Rallus, 128:267 podarces, Aphanocrex, 143:379 pollens, Tyto, 80:436 prenticei, Rallus, 104:99 pressa, Chen, 62:9 primus, Eocrex, 45:107 proavitus, Nautilornis, 13:394 prodromus, Palaeogyps, 20:5 pumilus, Corvus, 3:81 quadratus, Calohierax, 80:429 ramenta, Falco, 76:75 rftuax, Geochen, 100:146 iaurodoiw, Minerva, 4:455 senectus, Palaeonossax, 125:234 sternbergi, Palaeoplancus, 61:1 tantala, Ortalis, 54:64 n'tan, Leptotilos, 91:447 tridens, Meleagris, 44:33 troxelli, Palaeorallus, 45:108 typhoius, Buteo, 8:489 vagabundus, Moris, 40:89 veredus, Bathornis, 20:11 t/etusius, Neophrontops, 102:229 Collected Papers in Avian Paleontology Some Hypothetical Anatomical Stages in the Evolution of Avian Flight John H. Ostrom ABSTRACT T h e five known skeletal specimens of Archae- opteryx provide the only presently available ana? tomical evidence pertaining to the earliest stages in the evolution of the avian flight apparatus. This evidence, together with the osteology of modern birds, makes possible the reconstruction of some hypothetical anatomical stages that must have occurred during the course of avian evolution. It is postulated that one of the most critical compo? nents of the flight apparatus is the coracoid. Evo? lutionary changes in coracoid morphology elevated the actions of the principal humeral extensor (M. coracobrachialis) and forearm flexor (M. biceps), and as a consequence, caused deflection of the course of the M. supracoracoideus, converting it from a humeral depressor to a wing elevator. These changes appear to have been related to predation and feeding activities in the earliest birds, rather than to early stages of flight. Subsequently, addi? tional changes in the forelimb components pro? vided for restricted elbow and wrist movements, compact folding of the forelimb, and more stable support of the remiges. These last changes appear to have taken place after the acquisition of incip? ient flight capability. Introduction One of the most remarkable of all animal adap? tations is that of flight, which perhaps has reached John H. Ostrom, Department of Geology and Geophysics and the Peabody Museum of Natural History, Yale University, New Haven, Connecticut 06520. its zenith among vertebrates in the diverse kinds of flight displayed by modern birds. Strangely enough, there have been only a few investigations or specu? lations about the origins of avian flight, but per? haps that stems from the clear logic (Bock, 1965, 1969) of the currently favored" arboreal theory of flight origins (Marsh, 1880). T h e purpose of this paper, however, is not to explore that particular question, which I have already reviewed elsewhere (Ostrom, 1974), but rather it is to present purely theoretical reconstructions of some of the anatom? ical stages that must have occurred during the course of evolution of the avian flight apparatus, and to discuss the implications thereof. Reconstruction of such hypothetical evolution? ary stages is speculative to be sure, but it is a fruit? ful exercise in this instance because we know the nature of the starting point, the almost non-bird Archaeopteryx (Figure 1), as well as the "end point," the highly perfected flight apparatus of modern birds. A few authors (Heptonstall, 1970; Yalden, 1970) have investigated the possible flight capabilities of Archaeopteryx, but apparently no one has examined in any detail the anatomical changes that clearly must have occurred in the flight apparatus between the Archaeopteryx stage and that of modern birds. In the absence of any recognized intermediate stages within the avian fossil record, consideration of these necessary ana? tomical changes assumes major significance, since they may very well provide the only possible clues about early selective factors that led to the develop- aryx ItthoQrsph'cs v MEYER Eichstatt.Payem FICURE 1.?The Berlin specimen of Archaeopteryx lithographica found in 1877 near Eichstatt, Germany, in the Late Jurassic Solnhofen Limestones. Preservation of feather impressions, showing remarkably fine structural details, established these as the remains of a true bird, despite the fact that the skeletal anatomy is more like that of theropod dinosaurs than that of modern birds. (The scale is 100 mm long.) NUMBER 27 ment of powered avian flight. Conceivably, such considerations might even shed light on the actual beginnings of flight. A premise that is critical for the remarks that follow is that the several specimens of Archae? opteryx represent an extremely primitive stage in the evolution of birds (Ostrom, 1973, 1975). (I also believe that Archaeopteryx represents a preflight stage [Ostrom, 1974], but not everyone concurs with such an interpretation.) Some authors (de Beer, 1954; Swinton, 1960, 1964) have maintained that Archaeopteryx was not in the main lineage of avian evolution, but so far not one single bit of evidence has been found, either in the known speci? mens of Archaeopteryx or elsewhere, to support such a contention. Indeed, as Simpson (1946) ob? served, Archaeopteryx is anatomically intermediate between reptiles and modern birds, and regardless of whether it is directly ancestral to modern cari- nates, it is entirely reasonable to assume that the early main-line ancestry of birds included an ana? tomical stage comparable, if not identical, to that of Archaeopteryx. Thus, any consideration of the evolution of avian flight must start with Archaeopteryx. ACKNOWLEDGMENTS.?I gratefully acknowledge the assistance and courtesies of A. J. Charig of the British Museum (Natural History), London; H. Jaeger of the Humboldt Museum fiir Naturkunde, East Berlin; T . Kress of the Solenhofer Actien- Verein, Solnhofen, Bavaria; C. O. van Regteren Altena of Teyler's Stichting, Haarlem; and P. Wellnhofer of Bayerische Staatssammlung fiir Pala- ontologie und historische Geologie, Munich, who granted me the privilege of studying the speci? mens of Archaeopteryx in their care. I am also in? debted to Walter Bock, who read an early version of the manuscript and offered valuable suggestions and criticisms. These studies were funded by grants from the Frank M. Chapman Memorial Fund of the American Museum of Natural History, and the John T . Doneghy Fund of the Yale Peabody Museum. Flight Apparatus of Modern Birds By way of introduction to this section, certain generalized comparisons among higher vertebrates may be useful. In modern quadrupedal reptiles, the proximal components of both the fore and hind limbs extend laterally from the hip and shoulder joints (sprawling posture), which are situated well below the level of the vertebral column. In quad? rupedal mammals, both appendages are normally positioned in near-parasagittal orientation (up? right posture) articulating with hip and shoulder sockets that are close to the level of the vertebral column. In birds, the hip and shoulder sockets are both elevated and lie in or near the plane of the vertebrae. But birds are peculiar in that the hind limb projects downward in a nearly parasagittal orientation, whereas the forelimb extends out lat? erally from the body. These contrasting limb orientations in birds obviously are correlated with the different limb movements in the two modes of avian locomotion: terrestrial locomotion by means of alternating (or synchronous) longitudinal limb excursion in the hind quarters, and powered flight by means of complex, but chiefly synchronous (nonalternating) dorsoventral transverse move? ments of the forelimbs. The avian skeleton includes a number of spe? cializations that are directly or indirectly involved with powered flight: (1) T h e trunk region is quite rigid due to fusion or restricted articular freedom of the thoracic vertebrae, the solid bony connec? tion between the vertebral column and the sternum, by full ossification of the ventral (sternal) as well as the dorsal ribs, and the development of uncinate processes on the dorsal ribs. (2) Fixation of the shoulder joints by means of elongation of the coracoids which have developed solid bony articu? lations with a fully ossified sternum; fusion of the clavicles into a single median strut, the furcula, which appears to function as a spring-like spacer maintaining proper transverse spacing of the shoulder joints. (3) Complete ossification and en? largement of the sternum and the development of a deep and robust sternal keel. (4) Modification of the forelimb skeleton into a rigid but collapsible airfoil support in which the shoulder joint permits humeral movements in nearly all directions (in? cluding limited long-axis humeral rotation), but the elbow and wrist joints are restricted so as to confine forearm flexion and extension chiefly to the plane of the wing, wrist movements being limited to flexion and extension in the wing plane only; fusion of some carpals and metacarpals to provide a solid platform for the attachment of the primary remiges; and reduction of the manus to SMITHSONIAN CONTRIBUTIONS TO PALEOBIOLOGY digits I, II and III, with II and III united into a relatively rigid structure. Elsewhere (Ostrom, in press), I have given reasons for discounting the suggestion by some authors (Holmgren, 1955) that the remaining digits of the hand are II, III and IV. (5) The caudal vertebrae are reduced in number and coalesced into a short pygostyle, providing a firmer and more readily controlable base of attach? ment for the tail feathers. (6) Of particular impor? tance is the great development of the coracoids and furcula, which are constructed so as to prevent the shoulder sockets from being pulled downward or squeezed toward the midline by the powerful con? tractions of the flight muscles that originate on the sternum. In addition to these skeletal specializations, the pectoral and forelimb musculature of carinates have also been highly modified from the primitive tetrapod condition, to the extent that in some in? stances homologies are very much in doubt. For? tunately, the establishment of homologies is not critical for the theoretical reconstructions and in? terpretations that follow here. The flight muscula? ture of modern carinates has been studied and described by many authorities, among them Strese- mann (1933), Sy (1936), Fisher (1946), Hudson and Lanzillotti (1955), Berger (1960), and George and Berger (1966). From these studies, we may classify the flight muscles in six broadly functional categories as follows: (1) those that fix or adjust the pectoral girdle and the shoulder socket; (2) those that power the wing, producing the propul? sive down stroke; (3) those producing the recovery stroke of the wing; (4) the flexors, for folding the wing; (5) the extensors, for unfolding the wing, and (6) the muscles that produce minor adjust? ments of the wing components, including the remiges. Some thoracic and appendicular muscles are involved in two or more of these actions. The following tabulation summarizes the principal muscles in each of these generalized categories. In the discussion that follows, the emphasis will be on those muscles that are concerned with the power and recovery strokes of the wing, not because other muscles are less important, but because these are more conspicuously involved in the evolutionary changes that occurred between Archaeopteryx and later birds. SHOULDER JOINT FIXORS AND ADJUSTORS Rhomboideus superficialis Serratus superficialis Rhomboideus profundus posterior Serratus superficialis Serratus profundus anterior Sternocoracoideus FLIGHT MUSCLES Pectoralis superficialis WING RECOVERY MUSCLES Supracoracoideus Coracobrachialis anterior Deltoideus major anterior Deltoideus major posterior Deltoideus minor WING FOLDERS Latissimus dorsi anterior Latissimus dorsi posterior Scapulohumeral anterior Scapulohumeralis posterior Coracobrachialis posterior Subcoracoideus Subscapularis Biceps brachii Brachialis Flexor carpi ulnaris Flexor digitorum sublimis Flexor digitorum profundus Supinator WING UNFOLDERS Coracobrachialis anterior Deltoideus major anterior Triceps brachii Deltoideus major posterior Extensor metacarpi radialis Deltoideus minor Extensor digitorum communis WING ADJUSTORS Serratus superficialis metapatagialis Pectoralis propatagialis longus Pectoralis propatagialis brevis Cucullaris propatagialis Propatagialis longus Propatagialis brevis Expansor secundariorum Pronator sublimis Pronator profundus Entepicondylo-ulnaris Flexor carpi ulnaris Ulnimetacarpalis ventralis Extensor metacarpi radialis Supinator Extensor digitorum communis Extensor carpi ulnaris Powered avian flight is produced by synchronous down strokes of the wing caused by contraction of the large ventral muscle complex, the M. pecto? ralis. This complex usually consists of three or four distinct muscles, the M. pectoralis thoracica, or pectoralis superficialis, being the largest and most important. The other pectoralis muscles typically are small slips that function to tense the protopata- gium, thus belonging to the last category listed above. The M. pectoralis superficialis originates extensively on the posterior and lateroventral sur? faces of the sternum, the ventral half of the entire length of the carina, the entire posterolateral NUMBER 27 surface of the clavicle and the anterior margin of the sterno-coracoclavicular membrane. T h e pector? alis tendon inserts broadly on the ventral surface over most of the length of the deltopectoral crest (crista lateralis humeri) of the humerus. This mus? cle provides nearly all the force for flight and is the largest of all avian muscles, averaging more than 15 percent of total body weight among all flying birds (Hartman, 1961; Greenwalt, 1962). Two osse? ous features reflect the size and functional impor? tance of this muscle: the very large sternum and its carina, and the long and prominent deltopectoral crest of the humerus. Wing elevation (recovery stroke) is accom? plished by the combined actions of several mus? cles: the M. supracoracoideus, M. coracobrachialis anterior and Mm. deltoideus major and minor. Of these, the supracoracoideus is by far the most im? portant. T h e coracobrachialis, by virtue of its ori? gin on the anterodorsal extremity of the coracoid (the acrocoracoid) anterior and dorsal to the glenoid fossa, provides some lifting of the humerus, but its chief action is to extend or pull the hu? merus forward, thereby unfolding the wing. Typi? cally, it is the smallest "elevator" muscle. T h e M. deltoideus major usually consists of a pars anterior and pars posterior. The pars anterior arises from a small area on the dorsal side of the scapula adja? cent to the glenoid. T h e pars posterior originates on the dorsal end of the clavicle and the antero? dorsal surface of the scapula. Accordingly, these fibers tend to elevate the humerus and draw it forward. The M. deltoideus minor also originates on the anterodorsal apex of the scapula, above, medial, and slightly anterior to the glenoid, hence also acting to elevate the humerus. The largest humeral abductor, as noted above, is the M. supracoracoideus, also termed the pecto? ralis secundus or pectoralis minor (Figure 2). This muscle arises by extensive attachment on the dorsal parts of the sternal carina, the anterolateral sur? faces of the sternum, the ventro-anteromedial sur? face of the coracoid and the lateral part of the coracoclavicular membrane. Its fibers converge dorsally, attaching to a narrow tendon that passes backward through an osseous canal, the foramen triosseum, between the dorsal extremities of the coracoid and clavicle and the anterior extremity of the scapula. From there, the tendon turns down? ward to insert on the dorsal surface of the hu- S u p r a c o r a c o i d e u s T e n d o n Right H u m e r u s F u r c u l a L e f t C o r a c o i d P e c t o r a l i s S t e r n u m S u p r a c o r a c o i d e u s FIGURE 2.?Anterolateral view of the pectoral girdle and sternum of Columbia livia to show the general relationships of the M. supracoracoideus. The upper arrow indicates the course and action of the supracoracoideus tendon from the insertion toward the triosseal canal. The lower arrows indi? cate the location and action of the M. pectoralis, which has been removed in this drawing. (After Fig. III.l, George and Berger, 1966.) merus between the head and the deltopectoral crest. T h e fact that the triosseal canal is situated above the insertion point when the humerus is depressed allows this ventrally placed muscle to elevate rather than depress the humerus. Figures 2 and 3 illustrate the structure of the triosseal canal and its relationship to the supra? coracoideus muscle. Of particular importance is the very prominent dorsal process of the coracoid (the acrocoracoid) that extends well above and anterior to the glenoid. The medial side of this process forms the lateral wall of the triosseal canal and is the primary structural reason for the de? flected course of the supracoracoideus tendon. Medially, the dorsal extremity of the clavicle ar? ticulates with the upper medial surface of the acro? coracoid, forming the dorsomedial roof of the triosseal canal. A further factor of importance is that two important muscles arise from the upper anterior surface of the acrocoracoid, the M. cora? cobrachialis anterior and the M. biceps brachii. As noted earlier, the coracobrachialis anterior is a primary extensor of the humerus and the biceps is equally important as the principal flexor of the SMITHSONIAN CONTRIBUTIONS TO PALEOBIOLOGY a A c r o c o r a c o i d / C o r a c. -?C i ^S . ^ ^ ^ - B i c. b r -"""^ V : ::M$^..Jr S c a p u l a T r i o s s e a 1 C a n a l C o r a c o i d A c r o c o r a c o i d C o r a c o i d S t e r n a l B o r d e r G l e n o i d A c r o m i o n S u p r a c o r a c o i d F o r a m e n A c r o c o r a c o i d G l e n o i d \ s c o p u I a r B l a d e S t e r n a l B o r d e r F u r c u l o T r i o s s e a l C a n a l A c r o m i o n S c a p u l a 5 cm A c r o c o r a c o i d T r i o s s e a l C a n a l \ ' r FIGURE 3.?Four views of the left scapulo-coracoid of Catharles aura to show the nature of the triosseal canal, which is responsible for the reversed action of the M. supracoracoideus in modern carinates: a, lateral view; b, anterior view; c, dorsal view; d, medial view. (Bic. br. = the site of origin of the M. biceps brachii; Corac. = the site of origin of the M. coracobrachialis anterior. forearm. It is safe to assume that the elevated posi? tions of these origins at the apex of the acrocora? coid have functional significance. Without concerning ourselves with homologies, or the proper name for the avian "supracoracoi? deus," the action of that muscle in modern cari? nates emerges as extremely important for recon? structing some of the details of avian evolution. By the nature of its location and architecture, it is clear that at some earlier stage in the evolution of birds the antecedent of this muscle must have acted to depress the arm. Therefore, its action has been completely reversed, probably as a consequence of the development of the pulley-like arrangement of the triosseal canal and its interposition between the points of origin and insertion. T h e avian wing is elevated chiefly by this ventral muscle, rather than by dorsal muscles as we would expect, and as is the case in bats. The fact that virtually all muscles in all organ- NUMBER 27 isms follow the most direct route between the points of origin and insertion argues strongly against the possibility that the insertion of the supracoracoideus gradually migrated to the dorsal side of the humerus, without prior or concurrent deflection of the fibers or tendon leading to that insertion. Even if the insertion had shifted to a dorsal position on the humerus, contraction of the muscle would still depress, as well as rotate, the humerus-^unless the fibers approached the hu? merus from above. Consequently, the most logical explanation of the peculiar organization and action of the modern avian supracoracoideus would seem to be that its path was altered during the course of avian evolution. Modern carinates, together with the specimens of Archaeopteryx, establish that these postulated changes resulted from drastic changes in the shape of the coracoid and that these changes occurred subsequent to the Archaeopteryx stage. "Flight" Apparatus of Archaeopteryx The portion of the skeleton of Archaeopteryx that can be equated with the flight apparatus of modern carinates displays a number of important features: 1. There appears to be little or no loss of flexi? bility in the trunk region, either by vertebral fu? sion or by restriction of vertebral articular free? dom. Although fully ossified gastralia are present, there is no evidence of ossification of either sternal ribs or the sternum. Also, there are no uncinate processes on the dorsal ribs. 2. The pectoral arch does not appear to have been as rigidly fixed as in modern birds. The cora- coids are short, subquadrangular, not strut-like, and had only cartilaginous or membranous contact with the sternum. T h e clavicles, however, were fused and fully ossified into a robust furcula, but the nature of its contacts with the scapulocoracoid are not known. 3. Contrary to de Beer's (1954) interpretation, no sternum is preserved in any of the presently known specimens of Archaeopteryx (Ostrom, in press). This indicates that the sternum was almost certainly cartilaginous and probably lacked a keel. It may even have been membranous. Furthermore, the space anterior to the gastralia is quite short, a clear indication that the sternum, whether ossified or not, could not have been enlarged, as it is in all modern carinates. 4. The forelimb is elongated, but it does not possess any of the skeletal specializations of mod? ern carinates that are usually equated with avian flight. The deltopectoral crest of the humerus is comparable to that of small theropod dinosaurs and is longer and more elevated above the shaft than is typical of most carinates. T h e elbow and wrist joints are unmodified, the carpals and meta? carpals are not fused and digits I, II, and III are separate and unfused. T h e London and Berlin specimens clearly show that the forelimbs bore large, remex-like feathers, but it is uncertain whether these feathers were attached directly to the forelimb skeleton as in modern birds and as would seem to be required of true "flight" feathers. Despite exceptional preservation of several of the specimens, none shows anything that can reason? ably be interpreted as quill nodes on the ulna. This is negative evidence only, but a further indi? cation that the "flight" feathers were not firmly attached to the skeleton is the fact that imprints of the "primaries" of both wings in the London specimen are preserved with only slight disarray- ment, yet the left hand is disarticulated and the right hand is missing altogether. 5. T h e long reptilian tail of Archaeopteryx bore feathers, but there is no indication in any of the specimens that the caudal series was undergoing reduction or fusion into a pygostyle. On account of the feathers, we can conclude that the tail may have functioned as an aerodynamic, rather than an inertial, stabilizer, but this should not be construed as proof of flight capability in Archaeopteryx. The more important of the above conditions in Archaeopteryx are the nonavian form of the cora? coid, the absence of an ossified sternum, the un? fused carpometacarpus and the unfused digits of the manus. As Figures 4 and 5 show, the coracoid of Archaeopteryx is not elongated, and clearly did not serve as a strong, anticompressive brace against the sternum. It appears to have been fused with the scapula and its sternal border, although not as robust as the scapular margin, is well defined, but thin. The glenoid segment is stout, a relatively large supracoracoid foramen is present and a very prominent: lateral process occurs just anterior to and below the glenoid. This last feature, some- a S u p r a c o r a c o i d F o r a m e n G l e n o i d SMITHSONIAN CONTRIBUTIONS TO PALEOBIOLOGY S u p r a c o r a c o i d F o r a m e n B i c e p s T u b e r c I e \ B i c e p s T u b e r c l e G l e n o i d S t e r n a l B o r d e r A c r o m i o n S c a p u l a S c a p u l a 2 cm C o r a c o i d FIGURE 4.?Three views of the pectoral girdle of Archaeopteryx as reconstructed from the Lon? don, Berlin, and Maxberg specimens: a, anterior view of the left coracoid; b, lateral view of the left scapulo-coracoid; c, dorsal view of the left scapulo-coracoid. 1 20 ?0 FIGURE 5.?Left coracoid and glenoid of the London specimen of Archaeopteryx, as seen in anterior view from the underside of the main slab. (The smallest divisions on the scale equal 0.5 mm.) NUMBER 27 times referred to as the biceps tubercle (Walker, 1972), is of special significance because it appears to be the precursor of the avian acrocoracoid. Con? trary to Bakker and Galton's (1974) interpretation, the glenoid does not face downward, but is directed laterally (Figures 4 and 5) more or less as in mod? ern carinates (Figure 3). The Transition from Archaeopteryx to Modern Birds of the coracoid, anterior and ventral to the glenoid. With the humerus positioned in a horizontal transverse position, the biceps flexes the forearm anteroventrally toward the midline. But with the humerus extended forward, forearm flexion is down and backward. In birds, the site of origin of the biceps on the anterolateral surface of the acro? coracoid is situated in front of and above the glenoid; consequently, forearm flexion is restricted to a forward movement (Figure 6). CHANGES IN THE PECTORAL GIRDLE Before attempting to reconstruct hypothetical transitional stages in the evolution of the pectoral arch between Archaeopteryx and modern birds, it may be useful to review certain facts. First, the coracoid of all lower tetrapods, including birds, has certain constant relationships with other ele? ments of the trunk. It occupies a position between the scapula (with which it usually forms the shoulder socket) and the sternum, regardless of whether the latter is ossified or cartilaginous. Thus, at least two regions of the coracoid, the sternal border and the scapular border, are unmistakable reference points no matter what the shape or size of the coracoid. Similarly, the glenoid portion is always recognizable. T h e second consideration is the role of the cora? coid in forelimb biomechanics of lower tetrapods. Chief among the various muscles that attach to the coracoid (most of which insert on the humerus) is the biceps, the principal flexor of the antebrach- ium. (A structural and functional analog, the M. coracoradialis proprius, is present in amphibians.) The biceps passes between the coracoid and the internal proximal surfaces of the radius and ulna. Even in mammals, where the coracoid is no longer present as a separate bone, the major forearm flexor (which also happens to be termed the bi? ceps) originates on the presumed relict of the coracoid, the coracoid process of the scapula. T h e final consideration is that the location of the flexor origin relative to the glenoid fossa de? termines the approximate path of forearm flexion. Thus, for any given position of the humerus, the approximate orientation of the plane of forearm flexion can be determined from those two points. For example: the biceps brachii of lizards origi? nates on a small area adjacent to the sternal border FIGURE 6.?Dorsal aspect of the wing, skeleton and pectoral girdle of Corvus brachyrhynchos, showing the location and action of the M. biceps brachii (heavy arrow), the chief flexor of the forearm in modern birds. If, as seems reasonable, we accept the so-called biceps tubercle of Archaeopteryx as the homolog of the acrocoracoid of modern birds and the prob? able site of origin of the chief flexor of the forearm (whatever we call it), we can reconstruct the gen? eral nature of forearm flexion in Archaeopteryx. Although the precise orientation of the scapulo- coracoid in Archaeopteryx cannot be established from any of the presently known specimens, there can be little doubt that the biceps tubercle was situated well below and anterior to the glenoid (Figure 4b). Consequently, there must necessarily have been a major downward component in fore? arm flexion, regardless of whether the humerus was extended, retracted, or even adducted. Transformation of the avian coracoid from the condition in Archaeopteryx to that of modern birds involved two major changes: the dorsoventral elongation of the main body of the coracoid and the raising of the site of origin of the M. biceps brachii by anterodorsal prolongation of the acro? coracoid. Elongation of the coracoid increased the distance between the glenoid and the sternum, pre- 10 SMITHSONIAN CONTRIBUTIONS TO PALEOBIOLOGY A r c h a e o p t e r y x C a t h a r r e s FIGURE 7.?Hypothetical stages in the evolution of the avian coracoid from the Archaeopteryx stage to that of a modern carinate (Cathartes). The arrows indicate the hypothesized course of the M. supracoracoideus fibers in each stage and their progressive deflection resulting from evolutionary elevation and expansion of the biceps tubercle (= acrocoracoid). Upper arrows indicate the line of action of the supracoracoideus at each stage. Dashed lines indicate the acromion and adjacent regions of the scapula. All stages are of a left coracoid viewed from the front. sumably increasing the range of dorsoventral hu? meral excursion. This in turn may have been cor? related with the anteroposterior elongation of the sternum, the development of the sternal keel, and the enlargement of the ventral adductor muscles? the M. pectoralis. Increased force of forelimb ad? duction, for whatever biological role, required strengthening of the coracoid into a strong, anti- compressive strut between the shoulder socket and the enlarged muscle origins on the sternum. Because the supracoracoideus of lower tetrapods originates ventral and anterior to the glenoid, and because it also has a ventral origin close to the sternal border in modern birds, the primitive site of origin of this muscle in Archaeopteryx probably was in a similar position?ventral and somewhat medial to the biceps tubercle. If so, then any up? ward expansion of the biceps tubercle would have impinged against the supracoracoideus tendon, gradually deflecting its course medially around the base of the expanding "protoacrocoracoid." Once the base of this process reached the level of the glenoid, the then-deflected supracoracoideus would have pulled the humerus anteromedially, rather than downward. Continued expansion and eleva? tion of the acrocoracoid would have resulted in further deflection of the supracoracoideus. The action of this muscle almost certainly was not re? versed abruptly, but probably changed gradually from that of a humeral adductor, to an antero? ventral extensor, to a forward extensor, to an antero-dorsal extensor and finally becoming an abductor of the humerus. Figure 7 illustrates how this transformation may have taken place. If the above reconstruction is even approxi? mately correct, it is clear that one of the major factors in the evolution of avian flight structures was the upward expansion of the acrocoracoid. This conclusion is established beyond any doubt by the presently reversed action of the supracora? coideus in modern birds. T h e critical question is: What brought about the upward expansion of the acrocoracoid? There appear to be several possibili? ties: (1) elevation of the anterior part of the glen? oid and rotation of the shoulder socket to face di? rectly laterally, thereby permitting unrestricted transverse (up and down) movements of the fore? limb; (2) provision of an enlarged buttress at the level of the glenoid for the furcula to brace against, thereby insuring proper transverse separation of the shoulder sockets; (3) raising of the levels of humeral extension and forearm flexion by elevat- NUMBER 27 11 * \ FIGURE 8.?The furcula of Archaeopteryx as preserved in the London specimen. The exposed surface is probably the anterior surface. (The smallest divisions on the scale equal 0.5 mm.) ing the sites of origin of the coracobrachialis and biceps. In all probability, none of these factors acted alone, and other less obvious factors may have been involved as well. Whether enlargement of the pectoral adductor muscles and the elongation of the coracoids into robust struts occurred before, after, or concurrently with upward expansion of the acrocoracoid cannot be determined in the absence of intermediate stages in the avian fossil record. Whatever the se? quence, the upward growth of the acrocoracoid would have progressively deflected the action of the supracoracoideus. It also brought about signi? ficant changes in other forelimb movements, especially in elevating the range of humeral ex? tension and increasingly confining it to the cra- niad sector. As a direct consequence, the level of forearm flexion was also elevated to a nearly hori? zontal fore-aft plane more or less perpendicular to the transverse, up and down, humeral movements produced by the enlarged pectoral muscles. Considering these three possibilities, it appears that the glenoid in Archaeopteryx already faced laterally and slightly forward (Figure 4b,c) not ventrolateral^, as Bakker and Gal ton (1974) claim. T h e coracoid portion of the glenoid also seems to have been elevated. Yet, the biceps tu? bercle was still small and located well below the glenoid. Also, as was noted earlier, a robust furcula is present in Archaeopteryx (as seen in the Lon? don [Figure 8] and Maxberg specimens), and al? though the nature of its articulations with the other elements of the pectoral girdle is not clear, there does not appear to have been any special structure of the coracoid that might have served to buttress it, since, as already noted, the biceps tu? bercle is not elevated. This, of course, raises the question of the function of the furcula in Archaeo? pteryx. Did it serve as a transverse spacer between the shoulder sockets? If so, it would appear to have been related to some activity other than powered flight?perhaps predation. Since both the M. cora? cobrachialis anterior and the M. biceps brachii arise from the upper anterior surface of the acro? coracoid in all modern carinates, then by virtue of their positions above and in front of the glenoid, these muscles, respectively, pull the humerus for? ward and up, and flex the forearm forward and in? ward toward the midline. In Archaeopteryx, the humerus apparently could not be extended for? ward and upward above the level of the shoulder because no part of the coracoid was situated above 12 SMITHSONIAN CONTRIBUTIONS TO PALEOBIOLOGY and in front of the glenoid (Figures 4 and 9). Thus, of the three possibilities suggested above, the evolutionary expansion of the avian acrocora? coid would seem to have been most critically linked with the actions of the coracobrachialis and biceps muscles. There appears to have been some selec? tive advantage in raising the level or attitude of forelimb extension and forearm flexion. So far, I have given little attention to the scap? ula. This is because the scapula of Archaeopteryx already had acquired a form remarkably similar to that of modern birds, being very long, narrow and strap-like. Its principal distinctions from the con? dition in most modern birds are its fusion to the coracoid, the form of the acromion, and the shape of the distal extremity, which is rectangular or slightly flared in Archaeopteryx rather than ta? pered. The fact that the acromion is more promi? nent and robust than in most modern birds sug? gests that the M. deltoideus was perhaps a more A r c h a e o p t e r y x A c r o c o r a c o i d FIGURE 9.?Comparison of lateral views of the pectoral arch of Archaeopteryx and a modern carinate (Cathartes) to show the respective positions of the biceps tubercle and the acro? coracoid relative to the glenoid. The broken lines define the approximate dorsoventral range of humeral extension and forearm flexion possible in each as a result of contractions by the muscle that originated on those two processes. important humeral elevator at the Archaeopteryx stage of avian evolution. This would be consistent with the conclusion reached above that the supra? coracoideus of Archaeopteryx could not have ele? vated the humerus (as was noted by Walker, 1972), but rather must have been a lateral adductor. If the deltoideus, however, was more important as a humeral elevator at the Archaeopteryx stage than it is in modern carinates, then it would ap? pear that the force of the recovery stroke must have continued to decline in birds succeeding Archaeopteryx, until complete deflection of the supracoracoideus was accomplished. This implies that there probably was no tendency at the Archae? opteryx stage, or immediately afterward, toward powered flight. It should also be noted here that the stout acromion in Archaeopteryx may not have had any? thing to do with the deltoideus muscles, but might have served as a buttress for the stout furcula. This cannot be established on the basis of present specimens, however. The narrow form of the scapula, as compared with the broad, triangular form in all other tetra? pods except theropod dinosaurs, suggests that the musculature that inserted or originated on the scapular blade?and particularly on its dorsal sur? face?was greatly reduced. This certainly is true of modern birds in which the M. rhomboideus and M. s capu lohumera l (the largest dorsal shoulder muscles) are of relatively small size. T h e fact that this narrow scapular form occurs only in obligate bipeds (birds, Archaeopteryx, and theropod dino? saurs), but not in facultative bipeds (such as non- human primates, kangaroos, or ornithopod dino? saurs), or in any quadrupedal animal is highly suggestive. It indicates that strong stabilization of the pectoral arch by muscles connecting the scapular blade with the vertebral column and dorsal ribs, and powerful abduction of the limb by large mus? cles extending between the humerus and the scap? ular blade, were unnecessary in obligate bipeds in which the forelimb was no longer involved in weight support. CHANGES IN THE FORELIMB Comparison of the forelimb skeleton of Archaeo? pteryx with that of modern birds reveals several major differences, the most conspicuous of which NUMBER 27 13 1 : 2 0 0 0 20 60 FIGURE 10.?The right manus and carpus of the Berlin specimen of Archaeopteryx, seen in dorsal aspect. Notice the separated fingers and the unfused metacarpus and carpus, as well as the extent of lateral flexion. (The smallest divisions on the scale equal 0.5 mm. Roman numerals identify the digits.) occur in the hand and wrist. Figure 10 shows the right hand and wrist of the Berlin specimen of Archaeopteryx with its unfused metacarpus and three separated fingers. T h e same construction is present in the other three specimens in which the hands are preserved. This construction is in sharp contrast to the united metacarpus and manus of modern birds (Figure 11). It is obvious that phalanges have been lost or co-ossified in at least the external finger (digit III) of modern birds, but the most interesting changes have taken place in the metacarpus and wrist. Figure 12 illustrates the carpus and metacarpus as they are preserved in the Berlin (Figure 12a) and Eichstatt (Figure 126) specimens, compared with the same elements of a modern carinate, Cathartes aura (Figure 12c,Gi!). T h e first metacarpal is considerably shorter than the other two (Figure 10), as it is in modern forms, but it does not appear to be co-ossified with metacarpal II, nor are the second and third meta? carpals fused. T h e carpus consists of only three elements, a large distal carpal with a distinctive semicircular proximal profile, and two smaller bones, which probably represent the radiale (sca- pholunar) and the ulnare (cuneiform). Although neither of the last two elements resemble modern bird carpals, two features in Archaeopteryx do pre? view specialized conditions of the modern avian carpometacarpus. These are the large lunate distal carpal that is closely articulated with the first and second metacarpals (Figure \2a,b), and the in? ternal expansion at the base of metacarpal I. There can be little doubt that the lunate carpal of Arch? aeopteryx, by fusion with the two metacarpals, be? came the pulley-like trochlea of the carinate carpometacarpus. T h e proximal internal expan? sion at the base of the first metacarpal in Archaeo? pteryx is almost certainly the precursor of the large extensor process (processus metacarpalis I) of the modern carpometacarpus. In Figure 13, I have attempted to show how the modern avian carpometacarpus probably evolved from the con? dition in Archaeopteryx. Reconstructing the above intermediate stages is far simpler than trying to account for the condi? tions that brought about such changes. T h e second digit clearly was the dominant finger and ulti? mately became the main supporting structure of 14 SMITHSONIAN CONTRIBUTIONS TO PALEOBIOLOGY III Tr o c h l e a C a r p a I i s E x t e n s o r P r o c e s s FIGURE 11.?The right manus and carpometacarpus of Cathartes aura in dorsal aspect, for comparison with Figure 10. (Roman numerals identify the digits.) the primary remiges. The third or outermost finger gradually was reduced and metacarpal III was modified into a posterior (external) brace against metacarpal II. These changes could well have come about in connection with flight and the attachment of the primaries to the second meta? carpal, presumably bracing it against lift forces that would tend to rotate the second digit and metacarpal upward. Fusion of the lunate carpal to the metacarpus, and its expansion into the pulley? like trochlea, increased the degree of flexion pos? sible at the wrist, but at the same time reduced wrist mobility to the plane of the metacarpus and the wing. The prominent extensor process of the modern carpometacarpus is the point of insertion of the largest muscle of the avian forearm, the M. extensor metacarpus radialis, the action of which extends or unfolds the hand (Figure 14). In the discussion that follows, it is essential to distinguish between two very different kinds of flexing movements at the wrist: that in which the extremity is flexed toward the ulnar or external side of the forearm (termed lateral flexion here) and that in which the hand and metacarpus are "flexed" inward toward the radial side of the fore? arm. This last movement might be termed "me? dial flexion," but for the sake of clarity it is desig? nated here as "hyperextension." These terms differ from the usual terminology applied by ornitholo? gists (which by convention is in terms of a laterally extended wing), but hopefully they will be clear to all readers. T h e term extension is used here in the sense of straightening the wrist, and where neces? sary for clarity, it will be specified as extension from the laterally flexed or the hyperextended condition. In the Berlin and Eichstatt specimens of Arch? aeopteryx, the hands are flexed laterally toward the ulna at about 80 degrees to the radius and ulna. Close examination of the wrist in each case (Figure \2a,b), and especially of the morphology of the lunate carpal and the external aspect of the ulnar extremity, reveals that in both specimens the wrists are ftdly flexed. Notice that the internal condyle or condylus metacarpalis does not extend proximally along the outer surface of the ulnar shaft as it does in modern birds. For contrast, Fig? ure 12c shows the much greater maximum degree of lateral flexion (hyperflexion) possible in the modern bird wrist. Also conspicuous in modern birds is the elongated extensor process of the carpo? metacarpus, which greatly increases the leverage of the principal extensor of the hand. It is tempting to relate these features to some aspect of flight; for example, the need for adjusting or changing the surface area of the airfoil by im? proved efficiency and precision of extension and flexion at the wrist. Once flight capability had been achieved, increased leverage for the M. ex? tensor metacarpus radialis would reduce the amount of energy required to counteract the force of the airstream that tends to flex or fold the wing extremity laterally. On the other hand, during the power stroke, lift forces tend to open or extend the wing extremities. Another possibility is that the extensor process grew larger in conjunction with the development of wrist hyperflexion, which in turn was made possible by gradual expansion of NUMBER 27 15 L u n a t e C a r p a l '/^ ? Scapholunar ? R a d i u s E x t e n s o r P r o c e s s I >, S c a p h o l u n a r R a d i u s S c a p h o l u n a r R a d i u s R a d i u s U lna T r o c h l e a C a r p a I i s C u n e i f o r m U l n a C o n d y l u s M e t a c a r p a l i s FIGURE 12.?The wrists of Archaeopteryx (a and b) and Cathartes aura (c and d) as viewed from above: a, left wrist of the Berlin specimen; b, right wrist of the recently recognized Eichstatt specimen (b and c are preserved flexed laterally, toward the ulnar side of the forearm, to the maximum degree possible); c, left wrist of Cathartes drawn in the same laterally hyper- flexed position to show the greater degree of flexion possible in modern carinates; d, "exploded" dorsal view of the right wrist of Cathartes, flexed to the same degree as b, to show the specialized facets of the wrist elements, arrows indicating complementary articular facets. Notice in particu? lar the lengths of the external portions of the condylus metacarpalis of the ulna and also the trochlea carpalis of the carpometacarpus, as compared with the corresponding regions in Archaeopteryx. Also notice the large extensor process of the carpometacarpus compared with the modest expansion on metacarpal I of Archaeopteryx. The phalanges have been omitted from digit I in a and b. (Roman numerals identify the metacarpals; the horizontal lines equal 10 mm). the trochlea carpalis of the carpometacarpus and elongation of the condylus metacarpalis of the ulna. A critical point here, however, is that ex? treme hyperflexion of the manus has no obvious "flight" advantage, but it clearly is advantageous for compact folding of the forelimb extremities to protect the airfoil when not in use. Under these circumstances, it would appear that the increased extension leverage that was provided by a larger extensor process on the carpometacarpus was not related to the first explanation above, but prob? ably was advantageous for quick unfolding of a hyperflexed wing. This interpretation is reinforced when it is considered in conjunction with the unique linkage between the modern avian elbow and wrist that automatically synchronizes flexion (or extension) at those two joints. As first observed by Coues (1871) and Headley (1895), and con? firmed by Fisher's (1957) experiments, the radius of birds functions as a "connecting rod" between 16 SMITHSONIAN CONTRIBUTIONS TO PALEOBIOLOGY A r c h a e o p t e r y x C a t h a r t e s FIGURE 13.?Hypothetical stages in the evolution of the avian carpometacarpus from the Archaeopteryx stage to that of modern carinates. the elbow and wrist. Because of the greater length of the radial versus the ulnar condyle of the hu? merus, the radius slides distally along its axis when the elbow is flexed by the M. biceps, thereby push? ing against the carpus and metacarpus and forcing the wing extremity to flex. Extension of the wrist and elbow are similarly linked. In fact, because of the "connecting rod" action of the radius, and the increased leverage of the M. extensor metacarpus radialis provided by the enlarged extensor process, it is possible for that muscle to function as the primary unfolder of the entire wing, not just of the hand. Although smaller than the M. triceps brachii, the forearm extensor, the M. extensor metacarpus radialis of most carinates has far better leverage than the triceps (which inserts on the olecranon) for extending the wing extremity. It is not possible to establish which, if either, of the above possibilities was the decisive factor in the evolution of the modern avian wrist, but the specimens of Archaeopteryx seem to provide a clue. All four of the specimens in which the hand is preserved show what appears to be a maximum degree (about 80?) of flexion of the hands toward the ulnar side of the forearm. In other words, the hand could not be hyperflexed or folded back tightly against the forearm as in modern birds. Also, the extensor process is only very weakly de? veloped in these specimens. The nature of the articular surfaces in the wrists of the Berlin and Eichstatt specimens, however, indicates that the hands almost certainly could have been hyperex- tended medially, or bent toward the radial side of the forearm, to about the same degree that they are preserved flexed laterally toward the ulna, per? haps even more so. This last is important, because medial hyperextension of the hand is not possible in modern birds. In fact, the manus cannot even be fully extended to align parallel with the radius and ulna. From this, the most probable conclu? sion is that the extensor process is most important for recovery (extension) of the avian manus from a folded or laterally hyperflexed condition. If it had developed for enhancing medial hyperexten? sion it is difficult to understand why this process was retained, even enlarged, while at the same time FIGURE 14.?Dorsal view of the wing skeleton of Corvus brachyrhynchos to show the position and action of the M. extensor metacarpus radialis (heavy arrow), the chief extensor of the hand. NUMBER 27 17 the capacity for medial hyperextension of the hand was being reduced and ultimately eliminated. T h e rest of the forelimb appears to have been altered in much less conspicuous ways during the transition from Archaeopteryx to modern birds, yet those changes that can be recognized may have significant implications. In the ulna, the most ob? vious changes involved the external expansion and elongation of the condylus metacarpalis (Figure 12), the articular facet of which permits hyper? flexion of the manus laterally. Less obvious is the apparent lack of direct attachment of the second? ary remiges to the ulna, or of the primaries to the metacarpus, as is indicated by the absence of quill nodes. These conditions are lacking in the speci? mens of Archaeopteryx, but are well developed in a variety of modern carinates. T h e humerus of Archaeopteryx, although very bird-like, is much simpler than that of modern carinates. There is a long and well-defined delto? pectoral crest, but as can be seen in Figure 15, this crest projects farther from the shaft than is char? acteristic of most later birds. More important, though, are the features that are missing from the humerus of Archaeopteryx. There is no sign of either the external or internal tuberosity, nor is A R C H A E O P T E R Y X D e l t o p e c t o r a l C r e s t . H e a d E x t e r n a l T u b e r o s i t y H e a d D e l t o p e c t o r a l E c t e p i c o n d y l e B i c i p i t a l C r e s t I n t e r n a l T u b e r o s i t y there a bicipital crest. Distally, the ectepicondyle is also absent, or at least there is no detectable tubercle preserved in presently known specimens. In view of the other related features of the distal segments of the forelimb of Archaeopteryx, the absence of these processes seems to have special significance, because in modern carinates they play a direct part in the compact folding of the wing. T h e internal tuberosity (tuberculum mediale) is the site of insertion of the three principal humeral retractors (the M. subscapularis, M. subcoracoi- deus, and M. coracobrachialis posterior). The ex? ternal tuberosity (tuberculum laterale) is the site of insertion of the M. supracoracoideus which, in addition to elevating the wing, also rotates the en? tire folded wing dorsally toward the midline in modern birds. In Archaeopteryx, however, this mus? cle must have been a humeral depressor, as has been emphasized above. The bicipital crest (crista medialis) of modern birds is the area of insertion of the M. s capu lohumera l posterior, which draws the humerus back against the body. T h e implica? tions of these conditions are obvious: in the ab? sence of all specialized features of the humerus, ulna, and carpometacarpus that in modern birds are directly related to the folding of the wing, we are forced to conclude that Archaeopteryx was unable to fold the forelimb back against the body as in modern birds. Add to this the absence in Archaeopteryx of an ectepicondyle, which is the site of origin of the M. extensor metacarpus radi? alis, and also the weak development of the extensor process of metacarpal I, which is the site of inser? tion of this same muscle in later birds. These con? ditions indicate that powerful or rapid extension of the manus was unlikely, and probably not nec? essary, because the wrists of Archaeopteryx clearly show that lateral hyperflexion of the manus was not possible. On the other hand, a high degree of medial hyperextension was retained, perhaps as a critical action for prey catching or feeding activities. C A T H A R T E S FIGURE 15.?Comparison of the humeri of Archaeopteryx and a modern carinate (Cathartes), as viewed in dorsal aspect. Humeri are drawn to unit length for easy comparison, the relative sizes of each being indicated by the horizontal scale lines which equal 3 cm. The humerus of Archaeopteryx is devoid of most of the tubercles and crests that are well de? veloped in most modern birds. Most of these features are the sites of attachment of muscles that act to fold the wing. Discussion It would appear that the acquisition of obligate bipedal posture and locomotion in some pre- Archaeopteryx stage of avian evolution was re? sponsible in large part for the ultimate develop? ment of powered avian flight. An early consequence was the narrowing of the scapula. Strong stabiliza- 18 SMITHSONIAN CONTRIBUTIONS TO PALEOBIOLOGY tion of the scapula and shoulder joint, and powerful abduction of the forelimb became less critical than in obligate or occasional quadrupeds (whether of sprawling or upright posture), where antagonistic and synergistic interaction of dorsal abductors and ventral adductors are necessary for precise dynamic control of limb movements and positions under weight-bearing conditions. By the Archaeopteryx stage, forelimb abduction may have been accomplished solely by the action of a re? duced remnant of the M. deltoideus that presum? ably originated on the prominent acromion. With the assumption of upright, obligate bipedal posture and the release of the forelimbs from a weight-supporting role, new forelimb functions be? came possible. At the Archaeopteryx stage these functions apparently involved laterally elevated movements of the forelimb (as indicated by the outward facing glenoid), anteroventral extension of the humerus (as indicated by the anteriorly facing surface of the coracoid below the level of the glenoid?the only available site of origin for humeral extensors), and powerful anteroventral flexion of the forearm toward the midline (as in? dicated by the prominent biceps tubercle below and anterior to the glenoid?the most probable site of origin of the forearm flexor). T h e hands were capable of nearly 180 degrees of lateral flexion and medial hyperextension, as noted above. The ca? pacity for extreme hyperextension at the wrist (not possible in modern birds), coupled with the evidence for strong flexion of the forearm toward the sagittal plane, appears to be especially signi? ficant. Perhaps even more significant is the evi? dence that the forelimb of Archaeopteryx probably could not have been raised above the level of the glenoid when in the anteriorly extended position, simply because no part of the shoulder girdle was situated above and anterior to the glenoid. The strong anterior extensor (M. coracobrachialis an? terior) and forearm flexor (M. biceps brachii) of modern birds have their present actions only be? cause of the elevated positions of their origins on the acrocoracoid. The evolutionary upward expan? sion of the acrocoracoid would seem to have been linked causally with the actions of those two mus? cles and most especially with that of the humeral extensor. Selection apparently favored the eleva? tion of forearm and hand activities. As observed above, it is tempting to equate such changes with some aspect of flight. For example, these changes might permit alterations in the sur? face area of the "wing" by means of flexion or extension of distal components more or less in the plane of the "wing." Notice, however, that these capabilities apparently were not yet available in Archaeopteryx, where wrist and elbow movements were not restricted. Another possibility is that ele? vation of forelimb extension and forearm and hand flexion and extension ostensibly might im? prove the aerodynamic qualities of an incipient "wing" by making possible a positive angle of at? tack (where the leading edge of the airfoil is above the trailing edge, relative to the airflow or flight path). A positive angle of wing attack is essential for all forms of flight, whether powered or passive, because without it there can be no lift. T h a t being true, then there is a critical flaw in attributing the above anatomical changes between Archaeopteryx and modern birds to aerodynamic adaptations. The flaw is that there can be no lift, and thus no aero? dynamic selective advantage in raising the attitude of a potential airfoil until after the smallest degree of a positive angle of attack has been acquired. An aerodynamic explanation of the anatomical changes noted above is also weakened by the ab? sence of an ossified sternum in all specimens of Archaeopteryx. The absence of a sternum strongly suggests that the "flight" muscles of Archaeopteryx were not of unusual size, a conclusion that is sub? stantiated by the short space available for the ster? num in front of the ossified gastralia, as well as by the short nonstrut-like form of the coracoid. If all these assessments are correct, then some biological role other than flight must have been involved in the initial and early phases of the upward expan? sion of the biceps tubercle into the future acrocoracoid. Aside from making lift possible, the only other obvious consequence of raising the level of fore? limb extension and flexion is to place the hands and their activities directly in front of and above the animal. Two activities immediately come to mind: climbing and prey-catching. Various authors (Bock, 1965, 1969; de Beer, 1954; Swinton, 1960) have interpreted Archaeopteryx as being an arbo? real animal. I have argued that there is no compel? ling evidence for this (Ostrom, 1974), and instead, the skeletal anatomy of Archaeopteryx appears to have been adapted for ground-dwelling activities. NUMBER 27 19 Even if Archaeopteryx were arboreal, however, a possibility that I do not deny, then it acquired its climbing skills prior to elevation of the acrocora? coid and the capacity of elevated forelimb exten? sion, and after the acquisition of obligate bipedal posture. Obviously the same is true of prey-catching and feeding activities of Archaeopteryx.. If Archaeo? pteryx were insectivorous, as seems almost certain, it clearly must have been proficient at catching insects, whether it did so with its mouth by quick darting movements of the head on the long flexible neck, or by grasping them in the hands or snaring them beneath the forelimb plumage. Considering the general absence of flight-related skeletal struc? tures in the forelimb and pectoral girdle, it does not seem unreasonable to conclude that the fore- limbs of this obligatory bipedal predator must have taken part in prey-catching activities. If the forelimbs of Archaeopteryx were used to catch prey, and if the original advantages behind the enlargement of the contour feathers of the forelimb was to enhance insect-catching skills (Ostrom, 1974), there would be very real selective advantages in any changes that increased the scope of forelimb movements, especially if we think in terms of leaping or flying insects. At this point it is not possible to identify the exact activities or selective advantages that pro? moted the upward expansion of the acrocoracoid, but it seems clear that these were related to up? ward extension of the arms and hands. It also ap? pears that flight was not a factor in these first modi? fications. It was perhaps only coincidental that once a certain degree of upward enlargement of the acrocoracoid had been accomplished, the ac? tion of the coracobrachialis anterior would have been supplemented by the newly deflected supra? coracoideus acting as an anterodorsal extensor of the humerus. The various specialized features of the modern avian forelimb skeleton mentioned above (reduced fingers, fused carpometacarpus, novel tubercles and crests on the humerus) seem best explained as flight-related adaptations that appeared subse? quent to the dorsal expansion of the acrocoracoid and the resultant ability to raise the attitude of the extended forelimb, thereby achieving at least a minimal positive angle of attack. Fusion of the metacarpus would solidify the structural support of the primary flight feathers and brace the second metacarpal against long-axis rotation resulting from lift forces. Phalangeal reduction may have been correlated with changing the function of the manus to that of an airfoil and the reduction of the primitive prey-grasping role of the long, sepa? rated fingers. Fusion of the distal carpal to the metacarpus reduced the amount of abduction- adduction possible at the wrist, but at the same time facilitated precise flexion-extension of the manus in the plane of the wing, essentially per? pendicular to the powerful adductive actions of the enlarged pectoral muscles. The capacity for medial hyperextension of the manus was reduced and ultimately lost, presumably as the primitive avian hand became less and less involved with prey-catching and feeding activities and was in? creasingly adapted for flight-related functions. Later stages presumably involved development of structures related to compact folding of the wing and rapid unfolding?the various tubercles of the humerus noted above, the capacity for lateral hyperflexion of the manus, and the enlarged ex? tensor process of the carpometacarpus. Summary The existence of several specimens of Archaeo? pteryx, the oldest known fossil remains that are universally accepted as avian, provides important anatomical details of an extremely early stage in bird evolution. Despite impressions of what appear to have been modern-type "flight" feathers attached to the forelimb (but possibly not attached to the forelimb skeleton), the five presently known specimens of Archaeopteryx show almost no osteo- logical features that compare with the skeletal adaptations of the modern avian flight apparatus. T h e only exception is the furcula, preserved in the two largest specimens. Assuming that Archaeopteryx is in fact an an? cestral bird, and in the absence of any known intermediate structural stages in the avian fossil record between Archaeopteryx (of Late Jurassic age) and the essentially modern birds of Late Cretaceous and Early Tertiary ages, we can postu? late only the most obvious structural changes that occurred during the evolution of the avian flight mechanism. From the Archaeopteryx stage, the 20 SMITHSONIAN CONTRIBUTIONS TO PALEOBIOLOGY following sequence of developments seems prob? able, with the first two possibly taking place con? currently or, less probably, in reversed order: (1) Upward expansion of the biceps tubercle, thereby raising the sites of origin of the M. biceps and M. coracobrachialis and thus the level of humeral extension and forearm flexion?possibly in connec? tion with prey-catching or feeding activities, or perhaps to facilitate quadrupedal climbing. A di? rect consequence of the expansion of the acro? coracoid was the conversion of the M. supracora? coideus from a humeral adductor to a humeral elevator. (2) Enlargement of the pectoral muscles for more powerful arm adduction, accompanied by enlargement and ossification of the sternum, and elongation and strengthening of the coracoids to immobilize the shoulder joints. (3) Attachment of the remiges to the ulna and the second digit to resist feather deflection during the wing down- stroke. (4) Fusion of carpals and metacarpals into a united carpometacarpus for firmer fixation of the primaries, modification of the trochlea carpalis to permit only planar flexion and extension at the wrist, and loss of phalanges from all three fingers. (5) Loss of medial hyperextension of the hand and development of the capacity for compact folding of the wing, due to elongation of the condylus metacarpalis of the ulna and various tubercles on the humerus. This was associated with enlargement of the extensor process of the carpometacarpus to provide leverage for rapid unfolding of the wing. The occurrence of other changes in the musculo? skeletal system that affected the flight apparatus cannot be determined in the above sequence, but powered flight, as opposed to either gliding or flapping leaps, almost certainly could not have occurred before the first three of the above stages had been completed. Literature Cited Bakker, R. T., and P. M. Galton. 1974. Dinosaur Monophyly and a New Class of Verte? brates. Nature, 248:168-172. de Beer, G. 1954. Archaeopteryx lithographica. xi + 64 pages, 9 figures, 15 plates. London: British Museum (Nat? ural History). Berger, A. J. 1960. The Musculature. Chapter 8 in A. J. Marshall, editor, Biology and Comparative Physiology of Birds, Volume 1. 9 figures. New York: Academic Press. Bock, W. J. 1965. The Role of Adaptive Mechanisms in the Origin of Higher Levels of Organization. Systematic Zo? ology, 14(4):272-287, 6 figures. 1969. The Origin and Radiation of Birds. Annals of the New York Academy of Sciences, 167(1): 147-155. Coues, E. 1871. On the Mechanism of Flexion and Extension in Bird's Wings. Proceedings of the American Associa? tion for the Advancement of Science, 20:278-284, 2 figures. Fisher, H. I. 1946. Adaptations and Comparative Anatomy of the Locomotor Apparatus of New World Vultures. American Midland Naturalist, 35 (3): 545-727, 28 figures, 13 plates. 1957. Bony Mechanisms of Automatic Flexion and Ex? tension in the Pigeon's Wing. Science, 126:446, 1 figure. George, J. C, and A. J. Berger 1966. Avian Myology, xii + 500 pages, 248 figures. New York: Academic Press. Greenewalt, C. H. 1962. Dimensional Relationships for Flying Animals. Smithsonian Miscellaneous Collections, 144(2): 1-46, 17 figures. Hartman, F. A. 1961. Locomotor Mechanisms of Birds. Smithsonian Mis? cellaneous Collections, 143(1): 1-91, 7 figures, 5 tables. Headley, F. W. 1895. The Structure and Life of Birds, xx + 412 pages, 78 figures. New York: MacMillan. Heptonstall, W. B. 1970. Quantitative Assessment of the Flight of Archaeop? teryx. Nature, 228:185-186, 2 figures. Holmgren, N. 1955. Studies on the Phylogeny of Birds. Acta Zoologica, 36:243-328, 37 figures. Hudson, G. E., and P. J. Lanzillotti 1955. Gross Anatomy of the Wing Muscles in the Family Corvidae. American Midland Naturalist, 53:1-44, 35 figures. Marsh, O. C. 1880. Odontornithes: A Monograph on the Extinct Toothed Birds of North America, xv + 201 pages, 40 figures, 34 plates. Volume 7 of Report of the Geological Exploration of the Fortieth Parallel. (Professional Papers of the Engineer Department, United States Army, No. 18.) Washington, D.C. NUMBER 27 21 Ostrom, J. H. 1973. The Ancestry of Birds. Nature, 242:136. 1974. Archaeopteryx and the Origin of Flight. Quarterly Review of Biology, 49:27-47, 10 figures. 1975. The Origin of Birds. Pages 55-57 in volume 3 of F. A. Donath, editor, Annual Review of Earth and Planetary Sciences. 9 figures. Palo Alto: Annual Reviews Inc. In press. Archaeopteryx and the Origin of Birds. Linnean Society Biological Journal. Simpson, G. G. 1946. Fossil Penguins. Bulletin of the American Museum of Natural History, 87:1-100, 33 figures. Stresemann, E. 1933. Aves. Number 2 of volume 7 in W. Kukenthal and T. Krumbach, editors, Handbuch der Zoologie. Berlin: W. Gruyter. Swinton, W. E. 1960. The Origin of Birds. Chapter 1 in volume 1 in A. J. Marshall, editor, Biology and Comparative Physiology of Birds. New York: Academic Press. 1964. Origin of Birds. Pages 559-562, in A. L. Thomson, editor, A New Dictionary of Birds. 1 figure. Lon? don: Nelson. Sy, M. 1936. Funktionall-anatomische Untersuchungen am Vog- elflugel. Journal fur Ornithologie, 84:199-296, 52 figures. Walker, A. D. 1972. New Light on the Origin of Birds and Crocodiles. Nature, 237:257-263, 9 figures. Yalden, D. W. 1970. The Flying Ability of Archaeopteryx. Ibis, 113: 349-356, 4 figures. Evolutionary Significance of the Mesozoic Toothed Birds Philip D. Gingerich ABSTRACT Well-preserved fossils of the Mesozoic toothed birds Archaeopteryx, Hesperornis, and Ichthyornis, and of the bird-like dinosaur Compsognathus, dis? covered in the 19th century, indicated to early evolutionary biologists that dinosaurs and birds were closely related, and that birds in all proba? bility evolved from a dinosaur similar to Compso? gnathus. The modern ratites, sharing some distinc? tive similarities with Hesperornis, were regarded as survivors of a primitive initial radiation of birds. Several workers have subsequently challenged the idea that the Cretaceous birds Ichthyornis and Hesperornis had teeth or that they bore any simi? larity to the ratites. After careful study of the actual fossil specimens of Hesperornis, it is clear that this Cretaceous bird had toothed jaws and a palaeognathous palate, the latter condition being shared with ratites and certain dinosaurs. These and other characters place Hesperornis, like Arch? aeopteryx, in a position morphologically, as well as temporally, intermediate between dinosaurs and typical birds. T h e few significant features uniting the living ratites and tinamous all appear to be primitive characteristics, suggesting that ratites and tinamous are either survivors of an early radiation of birds, or are possibly a more recently derived artificial group in which primitive characters have reappeared secondarily through neoteny. Introduction The discovery of fossil birds with teeth was one of the most dramatic events in 19th century pale? ontology. In 1861 a partial skeleton of the Philip D. Gingerich, Museum of Paleontology, The Univer? sity of Michigan, Ann Arbor, Michigan 48104. feathered Archaeopteryx was discovered in the Jurassic deposits of Bavaria. In the next 16 years, skeletons of Ichthyornis and Hesperornis were dis? covered in the Cretaceous of North America and a more complete skeleton of Archaeopteryx was found in Germany. Surprisingly, the jaws of each of these birds bore reptile-like teeth. Being dis? covered only a few years after publication of The Origin of Species, toothed birds were much dis? cussed in connection with Darwin's evolutionary hypothesis. As spectacular as the original discoveries were, it is remarkable in retrospect how little detailed study was made of the actual specimens until rel? atively recently. T h e history of the original dis? coveries of toothed birds, the initial recognition of their evolutionary significance, and their subse? quent fate are reviewed here. T h e whole provides an interesting historical comment on the treatment of intermediate forms that do not conform to pre? conceived archetypical categorizations. ACKNOWLEDGMENTS.?I should like to acknowl? edge here the encouragement Dr. Wetmore gave to continued study of the Yale collection of Mesozoic birds when work was initiated on Hesperornis sev? eral years ago. My study of Hesperornis began, curiously enough, as a tutorial with K. S. Thomson on kinesis and jaw mechanics in fishes. Expanding the range of comparisons, the Mesozoic bird ma? terial at Yale was examined to determine the form of kinesis of primitive birds. When no simple an? swer was forthcoming, J. H. Ostrom authorized Peter Whybrow to undertake further preparation of the original specimens. Thus I am particularly indebted to Professors Thomson and Ostrom and to Mr. Whybrow for their assistance and encouragement. 23 24 SMITHSONIAN CONTRIBUTIONS TO PALEOBIOLOGY In addition, Drs. C. C. Black, T . H. Eaton, and L. D. Martin permitted an extended loan of the University of Kansas skull of Hesperornis. Drs. C. E. Ray, Nicholas Hotton III, and Mr. Robert Purdy allowed me to borrow the cranial material of Hesperornis in the National Museum of Natural History. Drs. W. J. Bock, Pierce Brodkorb, Peter Dodson, J. T . Gregory, Hildegard Howard, P. V. Rich, and M. V. Walker have all assisted one way or another as well. I also thank Mrs. Gladys Newton for typing the manuscript, and Mr. Karoly Kutasi for printing the illustrations. Margaret Egan read the manu? script and her comments have improved the paper considerably. Mesozoic Birds with Teeth It is now generally admitted by biologists who have made a study of the vertebrates, that Birds have come down to us through the Dinosaurs, and the close affinity of the latter with recent Struthious Birds will hardly be questioned. The case amounts almost to a demonstration, if we compare, with Dinosaurs, their contemporaries, the Mesozoic Birds. The classes of Birds and Reptiles, as now living, are separated by a gulf so profound that a few years since it was cited by the opponents of evolution as the most important break in the animal series, and one which that doctrine could not bridge over. Since then, as Huxley has clearly shown, this gap has been virtually filled by the discovery of bird-like Reptiles and reptilian Birds. Compsognathus and Archaeop? teryx of the Old World, and Ichthyornis and Hesperornis of the New, are the stepping stones by which the evolutionist of to-day leads the doubting brother across the shallow rem? nant of the gulf, once thought impassable. (O. C. Marsh, 1877:352). In 1859, perhaps the gravest deficiency of Dar? win's hypothesis of evolutionary descent was the rarity of intermediate forms in the geological record. Intermediate forms linking species into graded chains or linking major groups of animals to a common ancestor were at that time poorly known. Evidence remedying this deficiency was supplied in a most spectacular way by the discovery of several intermediate forms linking birds to a reptilian origin. Interestingly, each discovery of itself was insufficient to overcome archetypical cate? gorizations of birds and reptiles, and a truly evo? lutionary view of both classes was necessary in order to interpret literally the clear evidence for bird-reptile relationships offered by the skeletons of Compsognathus, Archaeopteryx, and Icthyornis. J. A. Wagner (1861) described a remarkably complete skeleton of a very small new dinosaur, Compsognathus longipes, from the Jurassic litho? graphic limestone of Solenhofen, Germany. In the same year H. von Meyer (1861) first published a notice on the skeleton of a bird from the same de? posit, which he named Archaeopteryx lithograph- ica. Having a dinosaurian skeleton, Compsogna? thus was clearly a variant of the "Reptile type." On the other hand, Archaeopteryx, with its dis? tinct impressions of feathers, was from the begin? ning regarded as a variant of the "Bird type." In? fluenced at least in part by Darwin's dynamic view of evolution, T. H. Huxley was able to overcome his contemporaries' fixed categorizations, even of groups as large as reptiles and birds, and he found in Compsognathus a bird-like dinosaur, and in Archaeopteryx the most reptilian of birds. Thus, Huxley (1868) confirmed the Darwinian expecta? tion of intermediate forms linking birds and rep? tiles in the fossil record. Although the actual common ancestor of living reptiles and birds had not been found, Huxley judged from their morph? ology that late Jurassic birds and reptiles were clearly much more closely related than their living descendants seemed to suggest. This closer simi? larity of the early forms was itself strong evidence favoring Darwin's dynamic view of evolutionary descent, as opposed to the then-prevailing view that living "reptiles" and "birds" were static groups persisting through time within some predetermined bounds. There was, however, a limit to the intermediate position even Huxley would accept for Archaeo? pteryx. Thus, of the single skeleton of Archaeo? pteryx then known, he wrote "unfortunately the skull is lost" (Huxley, 1868:70), making no men? tion of an earlier paper by Sir John Evans (1865) describing a premaxilla with four teeth preserved among the other bones of the specimen. Evans' note (1865:421) quotes a letter from von Meyer himself concerning the apparent association of a toothed premaxilla with Archaeopteryx: Teeth of this sort I do not know in the lithographic stone . . . . From this it would appear that the jaw really belongs to the Archaeopteryx. An arming of the jaw with teeth would contradict the view of the Archaeopteryx being a bird or an embryonic form of bird. But after all, I do not believe that God formed his creatures after the systems devised by our philosophical wisdom. Of the classes of birds and reptiles as we define them, the Creator knows nothing, and just as little NUMBER 27 25 of a prototype, or of a constant embryonic condition of the bird, which might be recognized in the Archaeopteryx. The Archaeopteryx is of its kind just as perfect a creature as other creatures, and if we are not able to include this fossil animal in our system, our short-sightedness is alone to blame. The presence of teeth in the bird Archaeopteryx was apparently too reptilian a characteristic for even Huxley to accept. O. C. Marsh was the first to discover the un? equivocal presence of teeth in primitive birds, though he too was at the outset apparently unable to accept the evidence. In September 1872, Pro? fessor Mudge of Kansas presented Marsh with some fossils from the Cretaceous Niobrara Chalk, the formation from which Marsh had earlier de? scribed the headless skeleton of a large, flightless, diving bird as Hesperornis regalis. Marsh studied Mudge's new fossils and in October published a note describing the postcranial skeleton as a new form of smaller volant bird, Ichthyornis dispar (Marsh, 1872a). A month later he published another note (Marsh, 1872b) on the jaws of a new small "reptile," Colonosaurus mudgei, found in association with the remains of Ichthyornis. In the same month that Colonosaurus was described (No? vember, 1872), Marsh's assistant T . H. Russell discovered a nearly perfect skeleton of Hesperornis, again in the Niobrara Chalk. This new skeleton included a skull with associated toothed jaws (Fig? ure 1). Immediately after the discovery of this skeleton of Hesperornis, Marsh published a short paper in February 1873 stating that the toothed jaws of "Colonosaurus" actually belonged to Ichthyornis. Of Ichthyornis dispar, Marsh (1873: 162) wrote: When the remains of this species were first described, the portions of lower jaws found with them were regarded by the writer as reptilian; the possibility of their forming part of the same skeleton, although considered at the time, was not deemed sufficiently strong to be placed on record. On subsequently removing the surrounding shale, the skull and additional portions of both jaws were brought to light, so that there cannot now be a reasonable doubt that all are parts of the same bird. Although no mention was then made of the toothed jaws of Hesperornis, that discovery prob? ably provided Marsh with the necessary corrobora? tion for him to accept the previously evident asso? ciation of toothed jaws with Ichthyornis. Two years after the toothed jaws of Hesperornis were first described by Marsh (1875), the Berlin specimen of Archaeopteryx was found about 10 miles from the original Solenhofen discovery, and its feathers, rep? tilian skeleton, and toothed jaws left no doubt about the reptilian ancestry of birds. Beyond their importance in dramatically filling a gap in the fossil evidence of evolution originally available to Darwin, the three early avian fossils Archaeopteryx, Ichthyornis, and Hesperornis are of interest for another reason. Huxley (1868:74) originally interpreted the great similarity of Compsognathus as indicating a dinosaurian (more specifically, coelurosaurian) origin of birds: Surely there is nothing very wild or illegitimate in the hy? pothesis that the phylum of the Class Aves has its foot in the Dinosaurian reptiles?that these, passing through a series of such modifications as are exhibited in one of their phases by Compsognathus, have given rise to the Ratitae?while the Carinatae are still further modifications and differentiations of these last, . . . Similarly, Marsh (1880:189) saw in the skull of Hesperornis certain resemblances to the "Rati tae," a group he regarded as being survivors of an evo? lutionary stage intermediate between reptiles and the true "ornithic type." Three principal ideas have come out of the early work of Huxley and Marsh: (1) that ratites are survivors of a primitive stock of birds, (2) that Hesperornis was similar to ratites, and (3) that Hesperornis and Ichthyornis actually possessed jaws with teeth. All three of these views have been challenged in the century since their first publi? cation by Huxley and Marsh. Disagreement with these ideas has come in part from authorities urg? ing caution in attempting any interpretation at all, but in most cases a strong contrary interpretation has been offered, usually without critical examina? tion of even the evidence available to Huxley and Marsh. Advocating ratites as a derived group of birds, reconstructing Hesperornis with a "neogna- thous" skull, and denying the presence of teeth in Icthyornis or Hesperornis have a common effect ?to deny the primitiveness and the reptilian char? acters of the best known Cretaceous birds and to maintain a wide gulf between birds and reptiles. This common effect of so many studies by post- Darwinian evolutionary biologists can only be ascribed to a deep-seated typological conception of "birds" and "reptiles"?an interesting comment on the pervasiveness of typological thinking. 26 SMITHSONIAN CONTRIBUTIONS TO PALEOBIOLOGY The Skull of Hesperornis Our knowledge of the structure of the skull in Hesperornis is based almost entirely on three speci? mens: (1) that found by Marsh and Russell in 1872, now in the Yale Peabody Museum (YPM 1206) (Figure 1); (2) the premaxillae and mandi? bles of a skull in the National Museum of Natural History, Smithsonian Institution (USNM 4978); and (3) a nearly complete but crushed skull in the collections of the University of Kansas (KU 22X7) (Figures 2 and 3). The first of these skulls was described and illustrated in some detail by Marsh (1880:5-12, plates 1,2), and a brief descrip? tion of the last two was published by Lucas (1903), who illustrated the quadrate and pterygoid of the Kansas specimen and the lacrimal of the National Museum specimen. The Yale and National Mu? seum specimens are very nearly the same size and both have been identified as Hesperornis rcgalis by virtually all workers. The Kansas specimen, on the other hand, is slightly smaller than the other two and was placed by Lucas (1903) in a new ge? nus, Hargeria, having as its type the species Hes? perornis gracilis Marsh. After extensive compari? son of the three skulls, I agree with Gregory (1952) that all three are of the same genus, Hesperornis. It remains an open question whether more than a single species should be recognized. The Yale skull was only partly removed from the enclosing rock by Marsh, and those portions that were freed for study were subsequently re? mounted on the original slab for display purposes. Consequently, the specimen was not really avail? able for examination until relatively recently, when it was removed from public exhibition. The Yale skull is in many respects the best one for study, because its components were scattered before fossilization and are now disarticulated and very little crushed (except for the braincase). The major portion of the Yale skull is illustrated here as it was mounted for exhibition (Figure 1). The braincase and some smaller fragments were com? pletely removed from the rock by Marsh and it is not certain that their positions as shown in Figure 1 are those in which they were found. T h e pre- FIGURI 1.?The Yale skull of Hesperornis regalis Marsh (YPM 1206), showing the individual disarticulated bones well preserved. Premaxilla, nasal, maxilla, and vomers are i l lustrated in the position in which they weie found?all have subsequently been removed and cleaned for study, (d = dentary, f = frontal, 1 = lacrimal, m = maxilla, n = nasal, pl = palat ine, pm = pre? maxilla, q = (juadrate, t = tooth, v = vomer.) Note presence of teeth in dentary, as i l lustrated by Marsh (1880, pl. 1). (Approximately one-half na tura l size.) NUMBER 27 27 maxilla, maxilla, nasal, vomers, and palatine, how? ever, were never removed and thus retain their original orientation as buried. It should be noted that Marsh had the nasal and maxilla exposed from both sides of the slab, but they were never completely removed. All of the important pieces of the Yale skull were carefully removed from their matrix in 1971 by Mr. Peter Whybrow, and they can now be studied freely and articulated. T h e cranium of the University of Kansas skull of Hesperornis is also in a slab of Niobrara chalk, but unlike the Yale specimen, it was preserved in articulation and both the braincase and the maxil? lary portion of the skull have suffered considerable crushing. Furthermore, Lucas (1903) reported that the specimen was preserved with the skull doubled backwards against the pelvis, and that portions of both the dorsal and the sternal ribs were crushed into the palate. It is possible to identify most of the bones preserved in this specimen, but the max? illae are conspicuously lacking?whether they are crushed beyond recognition into the palate or lost entirely cannot be determined. In addition to the portions illustrated in Figure 2, the Kansas specimen includes most of the lower jaws, a complete left quadrate, and a complete left pterygoid, which have been fully prepared and can be articulated with each other and also with the left palatine preserved with the main part of the cranium. T h e quadrate and pterygoid were illustrated by Lucas (1903, figs. 1,2; the left ptery? goid is incorrectly identified as a right pterygoid), and they are illustrated here in articulation (Fig? ure 3). T h e complicated S-shaped surface of the left pterygoid ("Apl" in Figure 3) articulates with the S-shaped proximal end of the palatine ("Apt" in Figure 2). The principal contribution of the USNM speci? men to our understanding of the skull morphology of Hesperornis is furnished by the nearly complete left lacrimal (illustrated by Lucas, 1903, fig. 3). By studying all three specimens it is possible to reconstruct the major features of the morphology of the rostrum, the palate, and the mandible (Fig? ure 4). T h e reconstruction has been discussed else? where (Gingerich, 1973), but some additional notes are added here. These notes and the illustra? tions of the Yale and Kansas specimens (Figures 1-3) are preliminary to a more definitive descrip? tion of this important material. They are intended to provide additional documentation of the re? markable completeness of the preserved specimens and to answer, in part, some questions raised by several skeptical colleagues. T h e length of the reconstructed skull was de? termined from the Yale specimen (YPM 1206). T h e dorsal surface of the braincase in this speci? men is crushed forward, but without affecting the length from the occipital condyle to the anterior end of the frontals. T h e overlapping articulation between the nasal and the frontal is outlined on the surface of the frontal, and the two can be fitted together as in life. T h e nasal-premaxillary articu? lation is preserved in both of the elements and these too can be fitted together accurately. As nei? ther frontals, nasals, premaxillae, nor the base of the braincase appear in any way distorted in length, a total length of 26-27 cm is estimated for this skull. Regarding the possibilities of cranial kinesis, little can be added to my previous discussion (Gingerich, 1973) except perhaps to add a more cautionary note. Rhynchokinesis in Hesperornis is almost certainly ruled out by the complete ring of bone formed by the premaxillae and nasals around the external narial opening. Some slight prokinetic movement might have been possible if the pre? maxillae and nasals were capable of being lifted off the frontals, although I know of no modern bird with such thick bone in the region of bending, and the complex interdigitation of the nasal and lacrimal in Hesperornis would likewise limit prokinetic movement. T h e quadrates were clearly streptostylic, which appears to have been corre? lated with a unique form of maxillokinesis whereby the maxillae were able to slide anteroposteriorly on rails formed by the nasal-premaxillary subnarial bars (Gingerich, 1973). While I am reluctant to postulate a form of kinetic motion so distinctive from that of any other animal, the preserved oste? ology of the rostrum in Hesperornis is unique and its adaptations were clearly different from those of any known vertebrate. Maxillokinesis appears to explain several unique features of the known fossil material. One of the most curious features of the upper jaw of Hesperornis is the fact that the premaxilla bore a horny sheath as in modern birds (indicated by t h e vascular nature of the underlying bone), while the teeth were confined to the maxillae 28 SMITHSONIAN CONTRIBUTIONS TO PALEOBIOLOGY FIGURE 2.?The Kansas skull of Hesperornis (KU 2287), ventral view as preserved, articulated on a slab of Niobrara Chalk. Note particularly the little-disturbed contact between the premaxillae and nasals, while the maxillae are completely missing. (Apt = pterygoid articulation of palatine, Aq = quadrate articulation of squamosal, n = nasal, pl = palatine, pm = premaxilla, v = vomer; approximately two-thirds natural size.) NUMBER 27 29 Asq FIGURE 3.?Articulated left pterygoid (pt) and quadrate (q) of Kansas specimen of Hesperornis (KU 2287): a, medial view; b, lateral view. Note particularly the complicated articulation between quadrate and pterygoid, the broad basisphenoid articulation of the pterygoid, and the complicated s-shaped articulation of the pterygoid with the palatine. (Abs = basisphenoid articulation of pterygoid, Am = mandibular articulation of quadrate, Apl = palatine articula? tion of pterygoid, Aqj = quadratojugal articulation of quadrate, Asq = squamosal articulation of quadrate; twice natural size.) proper. The lower jaw bore teeth throughout the length of the dentary. Secondly, in both the Yale and Kansas specimens, the maxillae have clearly separated from the nasal-premaxillary subnarial bars while, at least in the Kansas specimen, the subnarial bars were little disturbed by crushing. It should be noted also that the anterior end of each maxilla was grooved to fit over anteroposteriorly aligned keys or ridges of bone on the ventral sur? face of the premaxilla. This system of locking would keep the anterior ends of the maxillae from dropping away from the subnarial bars, while per? mitting anteroposterior motion of the maxillae relative to the subnarial bars. Finally, it now seems unlikely that the left and right vomers were fused to each other at their anterior ends. Such fusion would have prevented independent motion of the left and right maxillary segments of the palate relative to each other. The only possible functional advantage of having the kind of maxillary kinesis postulated here would be in moving each side inde? pendently. As evidenced by the unfused mandi? bular symphysis, such independent movement of the lower jaws was clearly possible. Independent movement of the maxillae would further expand the range of possible movements used in ingesting prey, which in this case was almost certainly fish. A new specimen of Archaeopteryx, described re? cently by Wellnhofer (1974), fortunately has a relatively well-preserved skull. Wellnhofer (1974: 185) interprets the skull as being definitely kinetic, but in Archaeopteryx, as in Hesperornis, it is dif? ficult to see where bending that would lift a signi? ficant portion of the rostrum could have taken place. Wellnhofer favors bending in the dorsal processes of the premaxillae, but at most this would lift only the tip of the upper jaw. Kinesis approach? ing that of modern birds seems not to have been present in either Archaeopteryx or Hesperornis. The present evidence bearing on Huxley's and Marsh's conclusions regarding the evolutionary position of the ratites, the relationship of Hesper? ornis to the ratites, and the presence of teeth in Hesperornis and Ichthyornis can now be consid? ered. The skeleton of Archaeopteryx is more rep? tilian than avian, and the uncontested fact that its jaws bear teeth is easy to believe. The skeletons of Hesperornis and Ichthyornis, on the other hand, are more typically avian. That a bird with an avian postcranial skeleton should have jaws with 30 SMITHSONIAN CONTRIBUTIONS TO PALEOBIOLOGY teeth has proved more difficult for some ornitholo? gists to accept. The quadrate is not preserved in the original specimen of Ichthyornis and the toothed jaws that Marsh found associated with this skeleton thus cannot be articulated with the remainder of the cranium. The articular regions of the original jaws are also badly distorted. Gregory (1952) made a careful study of the lower jaws of Ichthyornis and concluded that they belonged to a small mosasaur. Therefore Hesperornis alone was left with the combination of toothed jaws and a nearly typically avian skeleton. Inevitably, the as? sociation of teeth with the skull of Hesperornis was also questioned. Bock (1969) claimed that the teeth found with Hesperornis were not in place in the jaws, but scattered and cemented with matrix onto the skull. However, one need only examine the Yale specimen to see that teeth are preserved in the jaws as well as being scattered through the matrix (Figure 1). Discovery of a new, uncrushed posterior portion of a mandible of Ichthyornis (Gingerich, 1972), and its comparison with the mandibles of the original specimen and with those of Hesperornis and modern birds, leaves little doubt that Marsh was correct in associating toothed jaws with Ichthyornis. Interpretation of the structure of the palate in Hesperornis has had an interesting history. Marsh (1880:6) originally determined that the palate re? sembled most closely that of "Struthious" birds, but he confused the vomers with the palatines of his specimen of Hesperornis and gave no figure or reconstruction of the palate. Thompson (1890), followed by Lucas (1903), Shufeldt (1915), and Heilmann (1926), challenged Marsh's interpreta? tion of Hesperornis as indicating any relationship to the ratites. In the course of the 36 years from 1890 to 1926, the palatal structure of Hesperornis "evolved" rapidly in the literature, ultimately "converging" toward the neognathous palatal type of the modern loon (Gavia), a fish-eating, diving bird with certain similar locomotor adaptations. Fortunately, the Yale and Kansas specimens of Hesperornis (Figures 1-3) preserve virtually in? tact at least one example of each of the palatal bones. T h e quadrate and pterygoid are complete in the Kansas specimen, portions of both vomers are present in the Yale specimen (Figure 1), a crushed left vomer remains in the Kansas speci? men (Figure 2), and virtually complete palatines are preserved in both. About midway along their length, a rounded surface is present on the medial side of the vomers, which apparently articulated with the parasphenoid rostrum. T h e left maxilla is preserved in the Yale specimen (Figure 1) and it fits together with, and is overlapped by, the left vomer, as shown in Figure 4. There appears to be an articular facet on a ventrolateral expansion of the vomer for the narrow anterior end of the pala? tine (Figure 4). It is possible, but unlikely, that the palatines articulated directly with posterior projections of the maxillae (not preserved) rather than with the vomers. As noted above, the maxillae articulated with the subnarial bars formed by the premaxillae and nasals. Returning to the pterygoid- quadrate complex, it should be noted that each pterygoid bears a large, round, flat surface that articulates with a "basipterygoid" process of the basisphenoid (Figure 3, "Abs"). The entire reassembled palate is illustrated in Figure 4c. Compared with that of living ratites, the palate of Hesperornis is obviously different from an emu or an ostrich in being much longer and narrower. This lengthening has clearly been accomplished by elongation of the premaxillae, maxillae, vomers, and palatines relative to the more posterior elements of the skull. Although having adaptations quite different from those of any living palaeognathous bird, Hesperornis shares with palaeognathous birds all essential palatal characters that distinguish them from neognathous birds: (1) a relatively large vomer, (2) a firm pterygoid- palatine connection, (3) palatines widely separated from the sphenoid rostrum by the pterygoids, (4) strong basipterygoid processes of the sphenoid ar? ticulating with the pterygoids, and (5) a complex pterygoid-quadrate articulation including portions of the orbital process of the quadrate (Figure 3). The structure of the palate is still unknown in Archaeopteryx, but the presence of a palaeogna? thous palate in Hesperornis would appear to be strong evidence favoring the view that the pala? eognathous conformation is primitive in birds. Ad? ditional evidence bearing on the primitive struc? ture of the palate of birds is offered by this structure in theropod dinosaurs. Ostrom (1973) has compared the skeleton of Archaeopteryx with that of reptiles and concluded that birds originated from theropod dinosaurs, more specifically, from a coelurosaurian stock of theropods. T h e palatal NUMBER 27 31 FIGURE 4.?Reconstructed skull (a) and mandible (6) of Hesperornis regalis in lateral view; c, reconstructed palate in ventral view, (a = angular, ar = articular, bs = basisphenoid, d = dentary, f = frontal, j = jugal, 1 = lacrimal, m = maxilla, n = nasal, pl = palatine, pm = premaxilla, pt = pterygoid, q = quadrate, sa = surangular, sp = splenial, v = vomer) (From Gingerich, 1973.) structure is not known in any coelurosaur, but it is completely preserved in the large carnosaur Tyrannosaurus (Osborn, 1912) and less well pre? served in the smaller Dromaeosaurus (Colbert and Russell, 1969) and Deinonychus (Ostrom, 1969). The structure of each of these skulls appears to meet all of the criteria listed above for the palaeo? gnathous palate. Osborn (1912:11) noted this "analogy" implicitly in comparing the palate of Tyrannosaurus with that of a cassowary. The pres? ence of a palaeognathous palate in Mesozoic thero- pods, the "sister group" of birds, together with the palaeognathous palate of the Cretaceous bird Hesperornis, should leave little doubt that this palatal conformation is truly primitive in birds. I emphasize the strength of the evidence in this case because Cracraft (1974) has proposed that the living ratite birds are cladistically a "strictly monophyletic" group on the basis of their "de? rived" palaeognathous palate, their unique rham- phothecal structure, and their large ilioischiatic fenestra. Cracraft asserts that the palaeognathous palate is a derived state in birds, not a primitive one, because "it is restricted to a small number of species within this large class" (Cracraft, 1974:497). This specious reasoning would lead one to assume that teeth in Mesozoic birds are a derived condi? tion also, an unlikely hypothesis. The unique rhamphothecal structure and other resemblances of ratites and tinamous were inter? preted by Parkes and Clark (1966) rather less stringently than Cracraft now proposes. They (1966:469) noted that "resemblances are to be at? tributed to parallel evolution from a common stock . . rather than to convergence from unre? lated stocks, and thus, employing Simpson's con? cepts,^ the group may be considered monophyletic." The resemblance in rhamphothecal structure of 32 SMITHSONIAN CONTRIBUTIONS TO PALEOBIOLOGY ratites and tinamous provides no evidence that this group is strictly monophyletic in Cracraft's sense rather than monophyletic in G. G. Simpson's sense (i.e., possibly paraphyletic, if indeed the unique rhamphothecal structure is a derived state at all? it may very well be primitive). T h e third character Cracraft (1974:505) cites as evidence that ratites and tinamous are "each other's closest relatives" is their possession of a large ilioischiatic fenestra. Archaeopteryx has long been known to have a large ilioischiatic fenestra (see for example Petronievics and Smith Wood? ward, 1917), and Cracraft (1974:503) himself notes that this is the condition in Hesperornis and Ichthyornis. In short, of the three "derived" char? acters cited by Cracraft (1974), the first and third are almost certainly primitive and the second may be primitive as well. Evidence that ratites are strictly monophyletic remains to be discovered and it is possible, even probable, that the groups of living ratites and the tinamous are paraphyletic. Huxley (1867:419) en? visioned the living palaeognathous ratites as "waifs and strays" of an early radiation of birds, the neognathous types representing a subsequent radiation. Judging from the fossil record, succes? sive adaptive radiations replacing older stocks by newer ones are common in vertebrate evolution, and the class Aves is no exception. Although they are sometimes highly modified from the ancestral stock, we are fortunate to have in many groups of vertebrates surviving "waifs and strays," and still more fortunate to have well-preserved archaic fossil forms. In the absence of a more complete fossil record, some question must remain as to whether the modern ratites and tinamous are in fact sur? vivors of a primitive radiation of birds, or whether their primitive characteristics are neotenic solu? tions to particular adaptive problems, since both the palaeognathous palate and the open ilioischi? atic fenestra appear to be present in the develop? mental stages of modern nonratite birds (Jollie, 1958; Olson, 1973:35-36). T o explain away the primitive morphology of Hesperornis and ally it with modern loons and grebes (Cracraft, 1974:497, 503), however, illustrates on the one hand the arbitrary nature of the cladistic method of recon? structing a phylogeny, and on the other hand ex? emplifies another typological attempt to force an archaic bird into a modern morphological category. T o paraphrase von Meyer (1861), if Hesperornis does not fit our philosophical wisdom and if we are not able to include this fossil in our system, our shortsightedness is alone to blame. Literature Cited Bock, W. J. 1969. The Origin and Radiation of Birds. New York Academy of Sciences Annals, 167:147-155. Colbert, E. H., and D. A. Russell 1969. The Small Cretaceous Dinosaur Dromaeosauru<:. American Museum Novitates, 2380:1-49, 15 figures. Cracraft, J. 1974. Phylogeny and Evolution of the Ratite Birds. Ibis, 116:494-521, 10 figures. Evans, J. 1865. On Portions of a Cranium and of a Jaw, in the Slab Containing the Fossil Remains of the Ar? chaeopteryx. Natural History Review, new series, 5:415-421, 1 figure. Gingerich, P. D. 1972. A New Partial Mandible of Ichthyornis. Condor, 74:471-473, 2 figures. 1973. Skull of Hesperornis and the Early Evolution of Birds. Nature, 243:70-73, 2 figures. Gregory, J. T. 1952. The Jaws of the Cretaceous Toothed Birds, Ich? thyornis and Hesperornis. Condor, 54:73-88, 9 fig? ures. Heilmann, G. 1926. The Origin of Birds. 208 pages. London: H. F. and G. Witherby. Huxley, T. H. 1867. On the Classification of the Birds; and on the Taxonomic Value of the Modifications of Certain of the Cranial Bones Observable in that Class. Proceedings of the Zoological Society of London, 1867:415-472, 36 figures. 1868. On the Animals Which Are Most Nearly Inter? mediate between Birds and Reptiles. Annals and Magazine of Natural History, 4th series, 2:66-75. Jollie, M. 1958. Comments on the Phylogeny and Skull of the Passeriformes. Auk, 75:26-35. Lucas, F. A. 1903. Notes on the Osteology and Relationship of the Fossil Birds of the Genera Hesperornis, Hargeria, Baptornis, and Diatryma. Proceedings of the United States National Museum, 26:545-556, 8 figures. Marsh, O. C. 1872a. Notice of a New and Remarkable Fossil Bird. American Journal of Science, 3rd series, 4:344. NUMBER 27 33 1872b. Notice of a New Reptile from the Cretaceous. American Journal of Science, 3rd series, 4:406. 1873. On a New Subclass of Fossil Birds (Odontornithes). American Journal of Science, 3rd series, 5:161-162. 1875. On the Odontornithes, or Birds with Teeth. Amer? ican Journal of Science, 3rd series, 10:402-408, plates 9-10. 1877. Introduction and Succession of Vertebrate Life in America. American Journal of Science, 3rd series, 14:337-378. 1880. Odontornithes: A Monograph on the Extinct Toothed Birds of North America. Volume 7 of Report of the Geological Exploration of the 40th Parallel, xv + 201 pages, 34 plates, 40 figures. Washington: Government Printing Office, von Meyer, H. 1861. Archaeopteryx lithographica (Vogel-Feder) und Pterodactylus von Solenhofen. Neues Jahrbuch fiir Mineralogie, Geologie, und Palaeontologie, 1861: 678-679. Olson, S. L. 1973. Evolution of the Rails of the South Atlantic Is? lands (Aves: Rallidae). Smithsonian Contributions to Zoology, 152:1-53, 11 plates, 8 figures. Osborn, H. F. 1912. Crania of Tyrannosaurus and Allosaurus. Memoirs of the American Museum of Natural History, new series, 1:1-30, plates 1-4, 27 figures. Ostrom, J. H. 1969. Osteology of Deinonychus antirrhopus, an Unusual Theropod from the Lower Cretaceous of Montana. Yale University, Peabody Museum of Natural His? tory Bulletin, 30:1-165, 83 figures. 1973. The Ancestry of Birds. Nature, 242:136. Parkes, K. C , and G. A. Clark 1966. An Additional Character Linking Ratites and Tina? mous, and an Interpretation of their Monophyly. Condor, 68:459-471, 7 figures. Petronievics, B., and A. Smith Woodward 1917. On the Pectoral and Pelvic Arches of the British Museum Specimen of Archaeopteryx. Proceedings of the Zoological Society of London, 1917:1-6, 1 plate. Shufeldt, R. W. 1915. On a Restoration of the Base of the Cranium of Hesperornis regalis. Bulletins of American Paleon? tology, 5:73-85, plates 1-2. Thompson, DA. W. 1890. On the Systematic Position of Hesperornis. Uni? versity College, Dundee, Studies from the Museum of Zoology, 10:1-15, 17 figures. Wagner, J. A. 1861. Neue Beitrage zur Kenntnis der urweltlichen Fauna des lithographischen Schiefers, II: Schildkroten und Saurier. Abhandlungen der Bayerischen Akad- emie der Wissenschaften, Munchen, 9:65-124, plates 1-6. Wellnhofer, P. 1974. Das Funfte Skelettexemplar von Archaeopteryx. Palaeontographica, Abteilung A, 147:169-216, plates 20-23, 13 figures. The Skeleton of Baptornis advenus (Aves: Hesperornithiformes) Larry D. Martin and James Tate, Jr. ABSTRACT Baptornis advenus is a foot-propelled diving bird from the Late Cretaceous of Kansas. It was slightly larger than the largest living loon and had an un? usually long neck. T h e feet were large, with only slight modifications for toe-rotation. In this and many other respects, Baptornis was a less specialized diving bird than the contemporaneous Hesperor? nis. However, examination of almost the entire skeleton shows that Baptornis is more closely re? lated to Hesperornis than to any living diving bird and should be included in the order Hesperor? nithiformes. It should not be regarded as the earliest record of the Podicipediformes. We main? tain Baptornis in a family Baptornithidae separate from Hesperornithidae. Both Hesperornis and Baptornis are in many respects very primitive birds, which in some characters appear to be little modified from Archaeopteryx. Introduction In 1964 we discovered a previously unrecognized partial skeleton of Baptornis advenus in the col? lections of the University of Nebraska State Mu? seum. This specimen was more complete and bet? ter preserved than any other known example of the species and it encouraged us to review all known specimens of the form. In other institutions we found numerous examples of Baptornis. We were able to study all of these except a tarsometa? tarsus reported by Lambrecht (1933) to be in Larry D. Martin, Museum of Natural History and Depart? ment of Systematics and Ecology, University of Kansas, Law? rence, Kansas 66045. James Tate, Jr., P.O. Box 2043, Den? ver, Colorado 80201. Germany. We thus were able to reconstruct the skeleton of Baptornis advenus, apart from most of the skull and jaws. After Hesperornis and Ichthyornis, Baptornis is now the best known Cretaceous bird. It was first described by Marsh (1877) as a new swimming bird allied to Hesperornis, but readily separable from that genus in having the third and fourth trochleae of the tarsometatarsus of about equal size. He did not illustrate the type, but did give detailed measurements and commented that the bird was about the size of a loon and may have had similar habits. In 1880, Marsh illustrated the holo? type tarsometatarsus and mentioned a referred femur and tibiotarsus. Lucas (1903:553-555) de? scribed a partial skeleton housed at the University of Kansas, and illustrated the coracoid, humerus, radius, ulna, and patella. Shufeldt (1915:9-11, figs. 1-6) published photographs of the holotype and discussed it in great detail. Finally, Lambrecht (1933:258-260) summarized what was then known about the anatomy of Baptornis. After Lambrecht, relatively little has been pub? lished on Baptornis, although Swinton (1965) mentioned the genus briefly in his semipopular book Fossil Birds, and suggested that the Creta? ceous diving bird Lonchodytes might be related. Storer (1958), in his discussion of evolution in diving birds, made some remarks concerning the evolutionary position of Baptornis, although he mistakenly spelled Baptornis and Baptornithidae as "Bathornis" and "Bathornithidae". Walker (1967) reviewed some of the material and pre? vious work, but erroneously assigned an alleged large humerus to Baptornis. Other than the afore? mentioned works, the published references to Bap? tornis are restricted to checklists and catalogs 35 36 SMITHSONIAN CONTRIBUTIONS TO PALEOBIOLOGY (Wetmore, 1956; Brodkorb, 1963b), and discussion of these (Storer, 1965). A close relationship between Baptornis and Hesperornis was first suggested by Marsh (1877) and went essentially unquestioned until Brodkorb (1963b) placed the former in the Podicipedi- formes. Brodkorb's arrangement has been chal? lenged by Storer (1971) and by Martin and Tate (1969) on the basis of the new material discussed in detail below. Relationships also have been sug? gested between Baptornis and numerous other Mesozoic and Tertiary foot-propelled diving birds including Enaliornis, Lonchodytes, Hesperornis, Neogaeornis, and Eupterornis. Those with Enali? ornis and Hesperornis seem best established, as Baptornis seems to differ from these two genera only at the familial level, whereas it seems to have no affinities with the Podicipediformes. DISTRIBUTION.?Baptornis is known only from Kansas (Gove, Logan, and Wallace counties) and only from the Smoky Hill (upper) Member of the Niobrara Chalk Formation (Coniacian). Other North American Cretaceous birds (Ichthyornis and Hesperornis) are known from the present Gulf of Mexico to above the Arctic Circle in Canada (Russell, 1966), and range in age from the Turon- ian, Greenhorn Formation, to the Campanian, Pierre Shale (Walker, 1967; Martin and Tate, 1967). Baptornis is known only from marine deposits. A specimen from Logan County (KUVP 16112) and one from Wallace County (YPM 5768) are from very immature individuals, suggesting that Baptor? nis may have bred in the vicinity. Young specimens of Hesperornis are uncommon, although Russell (1967) reported several examples of subadult Hesperornis from a bituminous marine shale along the Anderson River in Canada (latitude 69? N) and suggested that a nesting colony might have existed nearby. The Niobrara Chalk is a carbonate deposit with no evidence of associated continental sediments. The absence of a shoreline would imply that Pteranodon, Ichthyornis, Hesperornis, and Bap? tornis were accustomed to venturing many hun? dreds of miles into open sea. Evidence for a nearby shoreline in Kansas in the Coniacian is somewhat sketchy and not completely convincing. The Nio? brara deposits do seem to thin, in an easterly direc? tion, toward areas that are known to have been continental in the Early Cretaceous. It also has produced a few examples of dinosaurs which are presumed to have floated out to sea after death. How far these dinosaurs may have floated is pres? ently unknown, but one wonders if it could have been hundreds of miles in such a scavenger-rich sea. MATERIAL EXAMINED.?All available specimens were studied. These included partial skeletons at the University of Nebraska State Museum, UNSM 20030; Field Museum of Natural History, F M N H 395; American Museum of Natural History, AMNH 5101; University of Kansas Museum of Natural History, KUVP 2290 and 16112; Yale Pea? body Museum, YPM 1465 and 5768. We were also permitted to examine some additional material at the Fick Fossil Museum, Oakley, Kansas. Most of the available hesperornithid specimens were also examined, and the extensive skeletal collection of recent birds at the University of Kansas Museum of Natural History was used for comparisons. ACKNOWLEDGMENTS.?The authors are deeply in? debted to the following persons for permission to use specimens in their care: C. B. Schultz, Univer? sity of Nebraska State Museum; R. Zangerl, Field Museum of Natural History; E. Simons and J. Ostrom, Peabody Museum of Natural History, Yale University; M. Walker, Sternberg Memorial Museum; R. Shaeffer, American Museum of Nat? ural History. We have also benefitted from conver? sations with P. Brodkorb, R. W. Storer, and J. Cracraft. M. A. Jenkinson read the manuscript and offered many helpful suggestions. The skeletal restoration was prepared by M. Tanner , the life restoration by B. Dalzell, and the other drawings by M. Tanner, D. K. Bennett, and D. Brennfoerder. Class AVES Subclass ODONTOHOLCAE Stejneger, 1885 Order HESPERORNITHIFORMES (Furbringer), 1888 AMENDED DIAGNOSIS.?Foot-propelled diving birds with teeth; skull paleognathous (at least in Hesperornis); mandibular symphysis not fused; re? duced wings; coracoid with glenoid facet on tip of scapular end; clavicles unfused; sternum flat; patella large and perforated for tendon of ambiens muscle; posterior extremities of ilium, ischium, and NUMBER 27 37 pubis separate; tibiotarsus lacking supratendinal bridge; tarsometatarsus lacking hypotarsal grooves and proximal foramina. Family BAPTORNITHIDAE American Ornithologist's Union, 1910 INCLUDED GENERA.?Baptornis and Neogaeornis. AMENDED DIAGNOSIS.?Foot-propelled diving birds with fully heterocoelous vertebrae; uncinate proc? esses turned dorsally (straight in Hesperornis); coracoid more slender than in hesperornithids; pelvis with the preacetabular portion of the ilium relatively longer than in hesperornithids; patella pyramidal in shape (much more laterally com? pressed in Hesperornis); intracentral bones not fused to caudal vertebrae; pygostyle long and later? ally compressed; outer trochlea of tarsometatarsus not enlarged; distal foramen on tarsometatarsus an open groove; toe-rotation not well developed. Genus Baptornis Marsh, 1877 TYPE-SPECIES.?Baptornis advenus. INCLUDED SPECIES.?Type-species only. AMENDED DIAGNOSIS.?Foot-propelled diving bird about the size of a Yellow-billed Loon (Gavia adamsii); neck elongate; wing greatly reduced, but radius and ulna present; tarsometatarsus not as compressed as in Neogaeornis. Baptornis advenus Marsh, 1877 LECTOTYPE.?Distal end of tarsometatarsus, YPM 1465. HORIZON.?Smoky Hill Member of Niobrara Chalk, Late Cretaceous. TYPE-LOCALITY.?Wallace County, Kansas. DIAGNOSIS.?Same as for genus. MORPHOLOGY SKULL.?The skull of Baptornis is known from only a few fragments. If teeth were present they were restricted to the maxillae and dentaries, as in Hesperornis. KUVP 16112 includes a fragment of the bill just anterior to the nasal openings. There are fairly large, distinct, triangular grooves on the lateral sides of the fragment, extending towards the tip. T h e sides of the bill are quite thick and vaulted. There is no evidence that the bill came to a point to form a spear as in the grebe Aechmo- phorus. A fragment of the left side of the bill (AMNH 5101) is probably from a position just posterior to that of KUVP 16112. This fragment shows a single large, elongate, longitudinal nu? trient foramen. In KUVP 16112 a large number of smaller foramina extend over the dorsal surface of the bill as in the top of the bill in loons. Appar? ently the tip of the bill was relatively short and broad, being shaped like that of Hesperornis (Marsh, 1880, pl. 1). It was probably covered by a horny sheath. AMNH 5101 includes a fragment of the frontal bone which is very difficult to orient (Figure la). T h e dorsal surface bears a faint scroll-like pattern similar to that on the frontal bone of grebes. How? ever, the frontal-parietal suture is present and the sagittal groove extends up to it, thus extending further posteriorly than in the grebes and indicat? ing that the top of the skull was more similar to that of loons. The cerebral hemispheres of the brain seem to have been expanded, as in modern birds, but better material is needed to confirm this. The ventral half of a right quadrate (Figure Ic-e) is preserved with A M N H 5101. The shaft is broad but not as massive as in Gavia. T h e orbital process has been broken off, but it had a tri? angular base and originated very low on the quad? rate. A prominent pit is present on the dorso- medial margin of the base of the orbital foramen, but the quadrate was not pneumatic. There is a small, rectangular facet for the articulation of the pterygoid. This facet is elongated dorsoventrally. Lateral to the pterygoid articulation is a shallow, rectangular depression from the middle of which a low ridge connects to the socket for the quadrato- jugal. The socket for the quadratojugal is large, shallow, and somewhat triangular in shape (rounded and very deep in loons and grebes). In loons and grebes, the mandibular articulation is divided into two parts by a groove, and the medial facet runs anteroposteriorly. Baptornis resembles Hesperornis in having a single comma-shaped facet running from the pterygoid articulation. The few fragments preserved are suggestive of a skull close to that of Hesperornis. Hesperornis and Baptornis have very similar quadrates, and both differ from loons and grebes in most details of that bone. 38 SMITHSONIAN CONTRIBUTIONS TO PALEOBIOLOGY FIGURE 1.?Skull elements of Baptornis advenus: a, fragment of the frontal (AMNH 5101), dorsal view; b, stereophotographs of posterior fragment of the left ramus (FMNH 395), dorsal view; c, stereophotographs of ventral half of the right quadrate (AMNH 5101), anterior view; d, same, ventral view; c, posterior view. (All X 4.) MANDIBULAR RAMUS.?FMNH 395 includes the posterior portion of the left mandibular ramus with the articular cotyla (Figure lb). It is slightly crushed dorsoventrally. T h e only other Cretaceous birds for which any part of the jaw is known are Hesperornis and Ichthyornis (excluding Caenagna- thus, which is not a bird). In Baptornis, the surangular is tightly fused to the articular, with a groove near the ventrolateral border of the specimen along the suture between NUMBER 27 39 these two bones. T h e articular cotyla is divided into anterolateral and posteromedial sections, which are separated by a low ridge. A groove, which includes the articular foramen, lies on the margin of the posterior cotyla and runs under the internal articular process. Anterior to the posterior articular surface is a small depression and a wide, deep groove, which forms at the junction of the surangular and the articular. The articular surfaces are of about the same shape and occupy approximately the same position as those on the ramus of Hesperornis (Gregory, 1952, fig. 7). They differ from the articular cotylae of the mosasaurs Clidastes and Platycarpus in hav? ing a concave, oblique, and elongate posterior articular surface and in the fusion of the jaw ele? ments. Like Hesperornis, Baptornis lacks a depres? sion for the condyle of the quadrate. This depres? sion is present on the jaws of modern diving birds. In the Double-crested Cormorant (Phalacrocorax auritus), for example, it is centrally located and occupies nearly the entire posterior articulation. A posterior articular foramen is similarly located in Hesperornis and modern species of birds, but is absent in the mosasaurs. T h e posterior portion of the ramus of Baptornis is remarkably similar to that illustrated for Ichthyornis (Gingerich, 1973; fig. 2). The mandibular articulation of Baptornis is very similar to that of both Hesperornis and Ich? thyornis (Figure 2.) T h e jaws of Cretaceous toothed birds are more similar to one another than is generally supposed. Hesperornis shares with Ichthyornis the following features: teeth flattened from side to side, with expanded bases; anterior end of dentary blunt and symphysis not fused; teeth restricted to dentaries and maxillae; quadrate articulation double. Gingerich (1972:472) lists several additional features shared by Ichthyornis and Hesperornis in the posterior portion of the ramus. In so far as we can tell, Baptornis also shares these characters, and although it cannot yet be proven, we suspect that it was toothed. PRESACRAL VERTEBRAE (Table 1).?AMNH 5101 contains the most complete vertebral series of Bap? tornis, with at least 22 presacral vertebrae present. UNSM 20030 includes the first eight vertebrae an? terior to the sacrum, and at least one of these is ab? sent from A M N H 5101 suggesting that the total number of presacral vertebrae in Baptornis may a FIGURE 2.?Posterior portions of left rami: a, Ichthyornis (from Gingerich, 1972), dorsal view, X 2.8; b, Baptornis advenus (FMNH 395), dorsal view, X 4; c, same, medial view, X 4. have been 23, the same as in Hesperornis. Most of the vertebrae with A M N H 5101 are fragmentary, however, which may cause errors in interpreting their number and position. It is possible that Baptornis may have had 24 or 25 vertebrae, but the number could not have been less than 23. There are four thoracic and parts of six cervical vertebrae with KUVP 16112. KUVP 2290 also con? tains four thoracic and six cervical vertebrae. F M N H 395 includes the last unfused thoracic ver? tebra. Three thoracic and two cervical vertebrae in A M N H 5101 and three cervicals with KUVP 2290 are preserved in articulation. These are the only natural associations available. T h e relative positions of the other vertebrae have been deter? mined by comparisons with Hesperornis. Only the cervicals reported on by Lucas (1903: 553) have previously been described. He pointed 40 SMITHSONIAN CONTRIBUTIONS TO PALEOBIOLOGY TABLE 1.?Measurements (mm) of the thoracic vertebrae of Baptornis numbered from the synsacrum foreward Character Length centrum Width anterior articulation Height anterior articulation Width posterior articulation Height posterior articulation Diameter of rib articulations Head Tuberculum Height neural spine Length base neural spine Width across transverse process FIRST UNSM 20030 19.5 18.3 9 14 9.5 * # 14 12 23 FMNH 395 18.7 17.6 8.8 12.8 8.5 * * 12 23.5 SECOND UNSM 20030 22 - 9 15 9.5 - - - KUVP 2290 22 18 8.5 - 10.5 - - - THIRD UNSM 20030 22 (14.5) 9 13 9.5 4.7 12 - KUVP 2290 (22) 16 8.5 15.5 9 - - - FOURTH UNSM 20030 21.5 - 8.7 12 9.5 4.7 13 - KUVP 2290 21 15 9 14 9 - - - FIFTH UNSM 20030 21.5 13 7.7 10.5 9 5.5 11 13 - KUVP 2290 (20) 14 10 - - 5 - - SIXTH UNSM 20030 21 13.5 8 11 9 4.5 3.5 8.5 13 36 Ribs do not occur on first vertebra; ( ) = measurements from crushed specimen. out that these were somewhat more elongate than the comparable vertebrae in Hesperornis. The atlas (lacking the dorsal arch) and the crushed anterior portion of the axis (Figure 3a) are present in A M N H 5101. The atlas is similar to the atlas of Hesperornis illustrated by Marsh (1880:196, fig. 40). In Hesperornis, loons, and grebes, however, the ventral border of the atlas is directed posteriorly to form a shelf. In Baptornis the ventral border of the centrum is directed an? teriorly and does not form a shelf. The hypapo- physis is short and broad so that it is not well separated from the rest of the centrum. On either side of the hypapophysis is a short posteriorly di? rected process. These are very small in Hesperor? nis and absent in the loons and grebes. Short, blunt, transverse processes are also present. The odontoid process of the axis is short and broad. T h e axis has a large, deep, anteriorly directed pit on its anterolateral side and a pair of small pits on each side of the midline on the anteroventral sur? face. Its centrum is very narrow, with a thin blade? like hypapophysis. The anterior cervicals are all narrow and elongate (Figure Sc-e). They become much shorter and more massive posteriorly. The first eight vertebrae after the axis seem modified for downward flexion (Figure 3) and the articular facets of the prezygapophyses curve ventrally. The anapophyses are short and somewhat dorsally di? rected. The sublateral crests form a triangle with the anteroventral margin of the centrum on most of these vertebrae. In Hesperornis, the sublateral crests on the anterior cervicals are nearly parallel and the centra are much broader ventrally. What appears to be the tenth vertebra is very narrow posteroventrally, with its posteroventral border di? rected downward. Articulating posteriorly with this vertebra is a short, broad eleventh cervical with the zygapophyses tilted laterally and not directed downwards. The ventral surfaces of this and the four following vertebrae are broad and short and bear low parallel sublateral processes that do not join each other ventrally as they do in similar ver? tebrae in giebes (Zusi and Storer, 1969, fig. 10). Vertebrae 14-16 bear very large, deep, lateral de? pressions in their centra. The ventral border of the centrum of the 16th vertebra is directed ventrally and forms a distinct, thick, ventral process. In Baptornis there is no evidence that large vertebrar- terial canals were present in as many vertebrae as they are in Hesperornis, loons, and grebes; how? ever, the vertebrae which should show these canals are all badly damaged in the material of Baptornis. The eighth vertebra anterior to the synsacrum (Figure 4a-d) corresponds to the 16th cervical vertebra of Hesperornis. Its dorsal spine is short, thick, and broad at its base. The tubercle is not bifurcated; the post- and prezygapophyses are set at a low angle and are widely spaced; the neural canal is circular in outline; the anterior articula? tion of the centrum is short dorsoventrally, but very wide; the transverse processes are wide, swing slightly upwards, and are directed posteriorly; the posterior border is thickened while the anterior portion nearest the centrum is slightly concave; and there is no vertebrarterial canal. On this ver- NUMBER 27 41 FIGURE 3.?Stereophotographs of vertebrae of Baptornis advenus: a, atlas and axis vertebrae (AMNH 5101), X 4; b, cervical vertebra (AMNH 5101), anterior view, X 1; c, same, ventral view, X 1; d, three partial cervical vertebrae (KUVP 2290), dorsal view, X I; e, same, lateral view, X 1; /, thoracic vertebra (KUVP 2290), posterior view, X 1. tebra the articulation for the tuberculum of the rib is shallow, circular in outline, and slightly re? cessed from the outermost margin of the diapo- physes. The articulation for the head of the rib is deep, circular, and placed anteriorly on the cen? trum. T h e centrum itself is short and thick, with a strong indentation on either side. T h e hypapo? physis is extremely short, stout, and directed pos? teriorly, practically merging in with the rest of the centrum. T h e distal hypapophysis is terminated by two stubby horizontal wings. The seventh vertebra anterior to the sacrum cor? responds to the last cervical of Hesperornis and resembles the previous vertebra. However, the an? terior articulation is not as wide and is higher dorsoventrally; the neural canal is not as rounded; the prezygapophyses are closer together and at a more acute angle; the dorsal spine is wider and thicker; there is a concavity on the anteroventral margin of the transverse process above the articu? lation for the head of the rib; and the transverse processes are shorter and do not swing back pos- 42 SMITHSONIAN CONTRIBUTIONS TO PALEOBIOLOGY FIGURE 4.?Stereophotographs of vertebrae of Baptornis advenus: a-d, dorsal, lateral, ventral, and anterior views of eighth vertebra anterior to the synsacrum (UNSM 20030); e-h, dorsal, lateral, ventral, and anterior views of first vertebra anterior to the synsacrum (USNM 20030). (All X 1.) teriorly. The articulation for the tuberculum of the rib is nearer the lateral edge of the diapophysis than in the 16th vertebra. The hypapophysis is thin and posteriorly directed. The sixth vertebra anterior to the sacrum re? sembles the seventh except that the anterior articu? lation is not quite as wide and is higher dorso? ventrally; the dorsal spine is of about the same height but is thinner; the transverse processes curve posteriorly; the pit above the articulation for the rib is deeper, and the hypapophysis is thin and directed anteriorly. The fifth vertebra anterior to the sacrum has a narrow, higher anterior articulation than the sixth; the centrum itself is not as indented and the pre? zygapophyses are closer together and at a more acute angle; the dorsal spine is thin, high, and directed anteriorly; the pit above the articulation for the head of the rib is deep, as in the preceeding vertebrae; the diapophysis and hypapophysis are NUMBER 27 43 missing, but enough remains of the hypapophysis to show that it was thin and large. The fourth vertebra anterior to the sacrum simi? larly has a high, narrow anterior articulation; how? ever, the centrum is less deeply indented; a small pit forms on the dorsal anterior margin of both of the postzygapophyses; the pit above the articula? tion for the head of the rib has become shallow and elongate. T h e dorsal spine, transverse proc? esses, right prezygapophysis, and most of the hypa? pophysis are broken off, but enough remains to show that the hypapophysis was thin, posteriorly directed, and probably short. The third vertebra anterior to the sacrum has a lower, but wider, anterior articulation; the centrum is less indented; the pit above the articulation for the head of the rib is absent; and the hypapophysis is very short, thin, and triangular. T h e dorsal spine and diapophysis are missing from the available specimens. The second vertebra anterior to the sacrum has a wider anterior articulation than the preceding vertebra. The top of the vertebra and the trans? verse processes are missing in the one available specimen. The articulation for the head of the rib is shallower than in the preceding vertebra, and there is a shallow pit just above it. The hypapo? physis is represented by a small knob on the ven? tral border of the vertebra. T h e centrum of this specimen had been broken through the middle and repaired with glue. We separated the two halves with acetone but found no medullary cavity. The first vertebra anterior to the synsacrum (Figure 4e-h) is distinctive. T h e anterior articula? tion is wider than in the preceding vertebra. The dorsal spine is high and thin, and the posterior margin is bordered by two small grooves lying on top of the postzygapophyses. T h e diapophyses are short, thick, and directed posteriorly, their ends being flattened to buttress against the inner sides of the ilia. There is a small pit lying directly an? terior to the diapophysis. T h e centrum is slightly indented, the ventral border is flat, and there are no rib articulations. The vertebrae of Baptornis are nonpneumatic and heterocoelous (amphicoelous vertebrae occur in Archaeopteryx, Ichthyornis, and Enaliornis). Compared to Hesperornis, the cervical vertebrae are more elongate and not as deep, the anapo- physes are less developed, and the sublateral proc? esses tend to converge more posteriorly. At least the first five postaxial vertebrae are modified for downward flexion, as are the presumed 14th and 15th vertebrae. T h e specimens of intervening vert? ebrae (7-13) are too fragmentary to be certain of their adaptations but some must have been modi? fied for upward flexion. The description of the thoracic vertebrae is based almost entirely on the beautifully preserved series with UNSM 20030. These all have good het? erocoelous articular surfaces, although circular pits (Figure 3/) occur in the centra of some speci? mens. They are not fused as in cormorants, or fused and further immobilized by ossified dorsal tendons, as in grebes. They also lack the very deep lateral excavations found in the thoracic vertebrae of Ichthyornis and can best be compared to the thoracic vertebrae of Hesperornis. As Lucas (1903) indicated, the hypapophyses are more anteriorly situated, not as well developed as in Hesperornis, and not bifurcated as in most modern diving birds. SYNSACRUM.?The synsacrum (Figure 5b-d) is represented in KUVP 2290, F M N H 395, A M N H 5101, and a few fragments from KUVP 16112. It is nonpneumatic and extremely narrow. Lucas (1903) reported that the synsacrum of KUVP 2290 contains 10 fused vertebrae and that the first bore a rib. Although he was correct in the number of vertebrae (10 also being the number found in F M N H 395) he was mistaken about the presence of a rib with the first fused sacral. Rib facets do not occur on any of the synsacra available nor even on the last unfused thoracic vertebra. T h e anterior sacral vertebra has a high, pos? teriorly sloping neural spine. T h e transverse proc? esses are tilted and flattened laterally to form a broad contact with the ilium. The second sacral is sutured dorsally to the first. It has a large, laterally flattened, pointed transverse process projecting an? teriorly (Figure 56) that also abuts the ilium. There are three vertebrae from the acetabulum forward, and these may represent fused lumbars with the rest of the sacrum being composed of seven fused caudals (urosacrals). T h e neural spines of the synsacral vertebrae are low and form a median ridge bounded by projections on either side. The posterior urosacrals lack the ventral keel found in Gavia, and the posterior central articula? tions of the last two urosacral vertebrae are divided 44 SMITHSONIAN CONTRIBUTIONS TO PALEOBIOLOGY ra FIGURE 5.?Pelvis of Baptornis advenus: a, right innominate bone (UNSM 20030), lateral view. Synsacra of B. advenus: b, dorsal view (KUVP 2290); c, lateral view (FMNH 395); d, ventral view (AMNH 5101). All X 1.) medially by a ventral groove. CAUDAL VERTEBRAE.?UNSM 20030 has five cau? dal vertebrae and a pygostyle, as does F M N H 395. AMNH 5101 also contains five caudals but in? cludes four anterior ones that are not represented in either UNSM 20030 or F M N H 395. T h e first caudal has already been discussed in the section on the sacrum. T h e following three vertebrae have low neural spines, flat ventral borders and widen posteriorly, assuming a triangular shape. All of these vertebrae are flanked by the pelvis and their transverse processes abut the ilia. T h e vertebrae posterior to the pelvis have high, straight, triangu? lar neural spines with rounded tips that become NUMBER 27 45 lcm FIGURE 6.?Caudal vertebrae and pygostyle of Baptornis advenus: a, dorsal view; b, lateral view. (X 1.) progressively lower posteriorly. T h e caudals also have large, posteriorly directed and ventrally de? pressed transverse processes that, along with the centra, become smaller posteriorly. T h e vertebral centra are either amphicoelous or amphiplatyan and the centra themselves are rounded ventrally and bear ventrolateral depressions or pits. The pygostyle is elongate and laterally flattened. It in? cludes five fused centra. T h e general configura? tion of the posterior two-thirds of the tail (Figure 6) is roughly similar to that in Gavia and quite different from Hesperornis, which has dorsoven? trally flattened caudals with wide, flat transverse processes and shelf-like, fused intracentral bones. Hesperornis has only two fused centra in its pygo? style. Intracentral bones are present in many living diving birds, but they have not been found in Baptornis. In Baptornis, the posteroventral margin of the second fused centrum of the pygostyle bears a distinct projection, which probably served as a muscle insertion. RIBS AND UNCINATE PROCESSES.?Some fragments of ribs are present with all of the specimens of Baptornis. The best material (Figure 7) is pre? served in situ on slabs of matrix with UNSM 20030. This material includes at least four different dorsal ribs and four different sternal ribs. These are flat? tened and shaped about as in Hesperornis, sug? gesting a narrow rib cage. Six uncinate processes representing five pairs are present in UNSM 20030. The uncinate processes of Hesperornis and Bap? tornis do not fuse to the ribs?a condition similar to that seen in grebes and loons, as well as certain other modern birds. In Hesperornis, the uncinate FIGURE 7.?Slab with ribs and uncinate processes of Baptornis advenus (UNSM 20030). 46 SMITHSONIAN CONTRIBUTIONS TO PALEOBIOLOGY processes are broad and straight. In Baptornis, they are narrow, and bend upward at an acute angle, thus resembling the uncinate processes of grebes (Figure 8). Because there is no association between ribs and uncinate processes on the slab, none can be placed in order with certainty. T h e ribs of Baptornis are heavier than those of grebes and loons and do not expand as much ventrally. T h e tuberculum is not separated as far from the head as it is in Hesperornis or in the modern foot- propelled divers. STERNUM.?The anterior and lateral margins of the sternum (Figure 9a) are preserved with UNSM 20030, the entire central portion and the posterior margin having been destroyed. In the area of the dorsal manubrial spine there is only a smooth, thickened border from which a shallow sulcus flares ventrally into a flattened, rounded ventral manubrial spine. The coracoidal sulci are deep, closely spaced, and lie at an angle of 22? from a line perpendicular to the midline of the sternum. The sternocoracoidal processes are large, rounded, flare laterally, and are not strongly curved. The costal margins are short, and bear five costal ridges. The sternum is most similar to that found in Hesperornis. It appears to bear a shallow rectangu? lar depression on its anteroventral surface which does not occur in Hesperornis. The sternum also TABLE 2.?Measurements (mm) of the coracoid of Baptornis Character UNSM KUVP 20030 2290 53 4 3.5 7.6 8 4.5 4.5 7 7.5 23 FIGURE 8.?Ribs and uncinate processes: a, grebe, Aechmoph- orus occidentalis; b, Baptornis advenus; c, Hesperornis re- galis. (Not to scale.) appears relatively smaller than in Hesperornis and consequently the body of Baptornis may have been somewhat narrower. T h e width of the anterior end of the sternum is 53 mm and the length of the costal margin is 27 mm. CORACOID (Table 2).?UNSM 20030 includes the scapular end and a fragment of the sternal end of the left coracoid. KUVP 2290 includes most of the right coracoid (Figure 9c). This specimen was illus? trated by Lucas (1903, fig. 6). The head of the coracoid is small and turned towards the procoracoid. The glenoid facet is large, elliptical, and shallow. T h e furcular facet is low, narrow, not undercut, and set almost directly on the scapular end of the shaft so that it is com? pletely visible when the scapular end of the cora? coid is viewed from above (Figure 10a, 11a). The surface of the scapular facet is rough and bears two or more distinct pits on its anterior end. The pro? coracoid is short and recurved towards the shaft to form part of the triosseal canal. Just below the procoracoid is a foramen leading into the shaft of the bone, which is probably the procoracoid fora? men. In KUVP 2290 this foramen penetrates from the anterior to the posterior surface, as well as branching into the shaft. Lucas (1903:553) incor? rectly states that the procoracoid process and fora? men are absent. T h e shaft is long and narrow. The posterior surface is slightly concave, while the an? terior surface is curved and convex. This gives the coracoid the appearance of a shallow spoon with a square end. T h e sternal end is wide, thin, and lacks definite facets. The coracoid of Hesperornis is fundamentally FIGURE 9.?Pectoral and wing elements of Baptornis advenus: a (top to bottom), anterior, ventral, and left lateral views of sternum (UNSM 20030) X 1; b, external and internal views of left humerus, X 1; c, ventral, dorsal, and external views of right coracoid (KUVP 2290), X \; d, distal end of right humerus, external view, X 5. NUMBER 27 47 a b 48 SMITHSONIAN CONTRIBUTIONS TO PALEOBIOLOGY Glenoid facet Scapular facet Triosseal canal CH '-'<: FIGURE 10.?Coracoids: a, tip of the scapular end of the left coracoid of Baptornis advenus; b-g, ventral views of the right coracoid: b, Baptornis advenus; c, Hesperornis regalis; d, Archaeopteryx lithographica; e, Aechmophorus occidentalis; f, Phalacrocorax auritus; g, Gavia immer. (Not to scale.) similar to that of Archaeopteryx. In both genera the coracoid is short and broad and the scapula and humerus have articulations on the tip of the scapular end. The coracoid of Baptornis resembles Hesperornis in these features, as well as in having the sternocoracoidal process above the midpoint of the bone. T h e main longitudinal axis of the shaft of the coracoid is perpendicular to the edge of the sternal facet in the Hesperornithiformes and in? clined in all other foot-propelled diving birds for which the coracoid is known (Figure 10). The coracoid of Baptornis is more elongate than in Hesperornis and the procoracoid process is smaller and differently shaped. In Baptornis, the internal edge of the coracoid is nearly straight, while in Hesperornis there is a large, square, internal pro? jection (Figure 10c). It should be noted that Lucas (1903, fig. 6) has illustrated the posterior view of the sternal fragment of the coracoid with the an? terior view of the scapular portion (compare his figure 6 with figure 10 of this paper). A small area for the attachment of the clavicle seems to be present although no clavicles are known. SCAPULA.?KUVP 2290 includes the articular end of the left scapula (Figure Ub-d), which was de? scribed and figured by Lucas (1903:553-554). The coracoidal articulation is long, narrow, and slightly curved to fit the contour of the scapular facet on the coracoid. It bears two large pits similar to those found on that facet. The anterodorsal margin of the proximal end does not show any articulation for the furcula. This margin slopes at about 47 degrees to the main axis of the shaft, and is ter? minated dorsally by a small projection. T h e ven? tral border bears a long, shallow groove. The measurements (in mm) of the scapula are: width of neck, 7.5; depth of neck, 4.0; width of proximal end, 10.5; length of glenoid facet, 9.4. The neck of the scapula is wide and thick, which led Lucas to suggest that it may have been ex? panded posteriorly as in penguins. T h e scapula of Hesperornis is similarly thickened, but does not expand posteriorly (Marsh, 1880:58). Therefore, the posterior portion of the scapula of Baptornis probably did not differ much from that of Hesperornis. HUMERUS.?KUVP 2290 includes the distal end and a portion of the shaft of the right humerus. This specimen was described by Lucas (1903:554), who reported it as being a left humerus, but the curvature of the shaft matches that of Marsh's illustration of the right humerus of Hesperornis regalis (Marsh, 1880, pl. 8: fig. 1). UNSM 20030 includes a slightly abraded proximal end and the greater portion of the shaft of the left humerus. We have examined the large alleged humeri of Baptornis reported by Walker (1967) and have determined that they are fragmentary shafts of the tibiotarsus. The proximal end of the humerus is simplified as compared with that of modern birds (Figure 9b). T h e shaft curves downward, then expands noticeably and is twisted posteromedially 75 mm from its proximal end. There is a nutrient fora? men situated in a groove 48.5 mm from the proxi? mal end in UNSM 20030. This foramen is like? wise present in KUVP 2290, which also has a NUMBER 27 49 FIGURE 11.?Stereophotographs of pectoral girdle elements of Baptornis advenus: a, scapular end of left coracoid (USNM 20030), internal view; b-d, ventral, internal, and external views of articular end of left scapula (KUVP 2290). (All X 4). second groove and a foramen 17.5 mm distal to the previously mentioned one. A small, rounded prominence set off from the internal condyle by a shallow groove may represent the distal external condyle. T h e internal condyle is not of the form usually found in birds and is only slightly delineated from the rest of the distal end. It bears a small foramen on its articular surface. There is no distinct olecranal fossa or prominent grooving. T h e shaft of the University of Nebraska 50 SMITHSONIAN CONTRIBUTIONS TO PALEOBIOLOGY specimen was x-rayed and the broken ends of KUVP 2290 and UNSM 20030 were examined. Neither are pneumatic. By transposing the hu? merus of UNSM 20030 over that of KUVP 2290 so that the curvatures and foramina are in align? ment (Figure 9b), a reconstructed length of 118 mm is obtained. This is only 18 mm more than Lucas's (1903:553) estimate of 100 mm based on KUVP 2290 alone. The width of the proximal end is 8.9 mm and of the distal end 6.8 mm. The greatest diameter of the shaft is 6.5 mm. The humerus of Baptornis is relatively long, curved, and rounded. It is not flattened and straight as in the wing-propelled auks and pen? guins. Lucas (1903:554) suggests that the wing may have been used in conjunction with the feet for locomotion. This seems unlikely, although we have shown it as having a stabilizing function (Figure 20). The humerus is larger than that of Hesperornis, which is a much bigger bird. In Hesperornis, the distal end is also much more re? duced and the radius and ulna may not have been present. RADIUS.?A description of the left radius (Fig? ure 126) KUVP 2290, appears in Lucas (1903: 554). The humeral cotyla is large and oval, with the bicipital tuberosity situated along its rim. T h e shaft expands markedly at about the midpoint. In this area there is a nutrient foramen on the palmar side and also a faint intermuscular line. The lunar depression is shallow. The scapholunar facet is long and narrow and the distal ligamental process is relatively large. The radius is 20.5 mm long, the proximal end is 3.0 mm wide, and the distal end is 3.5 mm wide. ULNA.?Lucas (1903:554) briefly describes the short, robust, left ulna, KUVP 2290 (Figure 12a). The olecranon process is short, massive, and not noticeably twisted as in many flying birds. The in? ternal and external cotylae on the proximal end are only slightly separated by an intercotyla area and almost form a single articular surface. T h e proximal radial depression is slightly discernable. The impression of the brachialis anticus is large and oblong, and crosses the palmar surface of the bone diagonally. A faint intermuscular line stretches for 2-3 mm below the distal end of the impression for the brachialis anticus. No nutrient foramen can be discerned. The distal radial depres? sion is small and quite shallow. T h e internal con? dyle on the distal end is a small projection. The external condyle is not a distinct ridge but bears a large, flat articular surface which tilts toward the anconal and ventral margins. Although we ex? amined the bone carefully, we could see no scars for feather attachment, Lucas' (1903:554) asser? tion of their presence notwithstanding. Measure? ments (in mm) of the ulna are: length, 21.6; width proximal end, 4.2; width distal end, 2.9; depth distal end, 3.5. T h e radius and ulna of Baptornis are short, stout bones resembling in general form their coun? terparts in the extinct diving goose Chendytes milleri (Howard, 1955). The reduction is much greater in Baptornis, however. In C. milleri the ulna is 43 percent as long as the humerus (How? ard, 1955:142), while in Baptornis it is only about 19 percent of the restored length (118 mm) of the humerus. T h e general form of the ulna is similar to that found in theropod dinosaurs (Figure 13) and it seems possible that the Hesperornithi? formes may have split off from the line leading to modern flying birds before the wing had developed the adaptations seen in modern birds. T h e pres? ence of well-formed articulations on the distal ends of the radius and ulna show that some sort of car- pals were present, although these may not have been fused into a true carpometacarpus. PELVIS.?All the specimens of Baptornis we studied included at least some fragments of the pelvis. Most of the right side is preserved with UNSM 20030, and our description of the pelvis is based on this specimen (Figure 5a). T h e synsac? rum is in place only in A M N H 5101, in which the acetabulum is opposite the third fused sacral. The pelvis is similar to that of Hesperornis, but differs in having a much longer preacetabular por? tion of the ilium. The postacetabular part of the ilium is quite long, as it is in all of the foot- propelled diving birds. T h e middorsal and the posteriormost portions of the ilium are not known, but were probably similar in shape to the same region in Hesperornis, although the whole pelvis is somewhat narrower proportionally. The pec- tinal process is broad and blunt, as it is in Hesper? ornis, and the acetabulum is partially closed. The acetabula of the loons and grebes have vertical sides and are completely open. T h e antitrochanter of Baptornis is large and rectangular, resembling that of Hesperornis. As in Hesperornis, the ante- NUMBER 27 51 FIGURE 12.?Stereophotographs of wing elements of Baptornis advenus: a, medial, palmar, and anconal views of left ulna (KUVP 2290), X 4; b, medial, palmar, and anconal views of left radius (KUVP 2290), X 4. rior end of the ischium sweeps up to form the posteroventral border of the antitrochanter, and there is a prominent suture here in both Baptornis and Hesperornis. On the pelvis of the Common Loon, Gavia immer, just anterior to the antitro? chanter, there is a small scar for the gluteus medius and minimus muscles. This scar is absent in the pelvis of grebes, Baptornis, and Hesperornis. The ilium and ischium of Baptornis are separate throughout their length, as they are in Hesperor- 52 SMITHSONIAN CONTRIBUTIONS TO PALEOBIOLOGY FIGURE 13.?Left ulnae: a, c, medial and palmar views of the theropod dinosaur Deinonychus antirrhopus (from Ostrom, 1969, fig. 58); b, d, same views of Baptornis advenus. (Not to scale.) nis. The ischium is long, thin, flattened internally, and rounded externally, so that in cross-section it appears bell-shaped. The pubis is long, heavy, and flattened dorsoventrally. It bears a shallow groove along the anterior quarter of its dorsal surface. T h e measurements (in mm) of the pelvis are: total length (estimated), 179; length of preace- tabular ilium, 54; depth of ilium anterior to pec- tinal process, 19; depth of ilium at pectinal process 27; greatest diameter of acetabulum, 14; height of antitrochanter, 13; width of antitrochanter, 11; length of free ischium, 103; length of free pubis, 109. Loons and grebes resemble each other and differ from Baptornis and Hesperornis in having the preacetabular portion of the pelvis narrower, twisted laterally, and spread apart anteriorly. Baptornis also differs from the modern foot- propelled diving birds in having the ventral mar? gin of the ilium turned medially (Figure 5). The origins of the iliotrochantericus medius and anti? cus muscles are ventral in Baptornis, but are dorsal in loons and grebes. T h e dorsal surface of the pre? acetabular ilium is turned medially in loons and grebes and laterally in Baptornis. T h e postace- tabular portion of the pelvis of Baptornis is, on a whole, narrower than in other diving birds except Hesperornis. FEMUR (Table 3).?Both femora are represented in FMNH 395 and KUVP 2290. UNSM 20030 has the right femur present (Figure 146) and KUVP 16112 includes fragments of both femora. The femur of Baptornis is proportionately more elongate than that of Hesperornis; the neck is more constricted; the insertion of the round liga? ment is smaller; and the trochanter rises slightly above the head, whereas both are of about the same height in Hesperornis. When the femur is articulated with the pelvis its position is more in? clined than in Hesperornis, but the difference is probably not as great as Lucas (1903:554) sug? gested. The iliac facet occupies about the same shape and area as it does in Hesperornis, and the obturator ridge is very similar in form. Baptornis resembles loons in having the lateral margin of the trochanter close to and parallel with the axis of the shaft, whereas the lateral margin of the tro? chanter extends a considerable distance away from the axis of the shaft in Hesperornis. T h e anterior intermuscular line sweeps down in a low arc from the trochanteric ridge to the external condyle. The posterior intermuscular line is not well defined, but runs down the medial surface of the bone from just below the head to the internal condyle. The trochanteric ridge is proportionately larger and heavier than it is in Hesperornis. There are no large nutrient foramina evident on the shaft. The popliteal area is broad and shallow. The fibular condyle sends off a distinct wing in Baptornis and Hesperornis and there is a thick connection be? tween the internal and external condyles (this connection is thick in cormorants and grebes and thin in loons). The fibular groove is broad and shallow in Baptornis and Hesperornis. T h e inter? nal condyles are at about the same level in Hes- TABLE 3.?Measurements (mm) of the femur of Baptornis Character Length Diameter head Diameter distal articulation Diameter proximal end Antero-posterior diameter midshaft Transverse diameter midshaft UNSM FMNH KUVP 20030 395 2290 71 10 25 24.5 11.5 10 72 10 24 24.5 12 10.5 75 11.5 26 28 12.5 11 NUMBER 27 53 a , : b I FIGURE 14.?Hindlimb elements of Baptornis advenus: a, distal end of left tibiotarsus (UNSM 20030); b (top to bottom and left to right), proximal, distal, anterior, lateral, posterior, and medial views of right femur (UNSM 20030); c (top to bottom and left to right), proximal, pos? terior, and anterior views of right fibula (UNSM 20030); d (top to bottom), anterior, posterior, and distal views of right patella (UNSM 20030). (All X 1.) 54 SMITHSONIAN CONTRIBUTIONS TO PALEOBIOLOGY perornis while the external condyle is much more distal than the internal condyle in Baptornis. A discussion of the muscle scars on the femur would be valuable but the homologies are difficult to ascertain. Those of the following scars seem fairly certain. Along the posterior intermuscular line, just below the head, is a small raised triangu? lar area which may correspond to the insertion of the M. iliacus. On the lateral surface of the femur, along the trochanteric ridge, is a complex region of muscle attachments resembling the same area in Hesperornis. T h e tubercle for M. piriformis is not as prominent as it is in Hesperornis and is situated about half way up the shaft. The proportions of the femur of Baptornis sug? gest that the legs were not bound so closely to the pelvis as in Hesperornis and may have had slightly greater freedom of movement. In Hesperornis, the femora may have been permanently held in the ex? tended position illustrated by Heilmann (1927, fig. 34), while Baptornis may have been able to rotate the legs ventrally for paddling and then ab? duct them for diving as do some diving ducks (Raikow, 1970:6). PATELLA (Table 4).?The patella of KUVP 2290 was described and illustrated by Lucas (1903). There is also an excellently preserved patella with UNSM 20030 (Figure I4d). This is a short tri? hedral bone resembling in some respects the patella of a cormorant. The foramen for the ten? don of the ambiens muscle is large and perforate. The articular surface on the base of the bone is double, indicating that it probably articulated with both the internal and external condyles of the femur. In Hesperornis there is a single con? cave surface, which articulated with the external condyle of the femur. Therefore, the patella of Hesperornis would have been lateral to the main axis of the tibiotarsus, while that of Baptornis would almost have been centered on it (contrary to Lucas, 1903:554). Cormorants have the patella TABLE 4.?Measurements (mm) of the patella of Baptornis TABLE 5.?Measurements (mm) of the tibiotarsus of Baptornis Character Character Length Distal antero-posterior diameter Distal transverse diameter Diameter ambiens foramen UNSM 20030 19 10.5 16 6 KUVP 2290 20.5 13.5 16.5 7 UNSM FMNH KUVP 20030 395 2290 195 14 18 9 12 19 194 13 17 8.5 11.5 18 - 14 18.5 - - - Length Elevation cnemial process Diameter proximal articulation Antero-posterior diameter shaft* Transverse diameter shaft* Diameter distal end * Below fibular ridge. placed as in Baptornis. The patella in grebes is shaped as in Hesperornis and articulates on the external condyle of the femur. However, grebes lack the ambiens muscle and therefore no fora? men is present in the patella. TIBIOTARSUS (Table 5).?Both right and left tibiotarsi occur in UNSM 20030 and in FMNH 395 and parts of both are present in KUVP 2290 and 16112. The tibiotarsus (Figure 15) is like that of Hes? perornis in being elongate and nonpneumatic (like Hesperornis, it has a large medullary cavity). The proximal end flares out as in Hesperornis due to the lateral expansion of the outer cnemial crest. This region is not as expanded in loons and grebes. As in Hesperornis, the inner cnemial crest is low, so that the groove between the two crests is broad and shallow. In loons and grebes, the inner cnemial crest is high and the surface between the two crests is narrow and deeply excavated. The rotular process is lower than in loons or grebes and is similar to Hesperornis. The external articular surface is small and slopes ventrally. It is not as rounded as in loons or grebes, nor is it set apart anteriorly and posteriorly from the inner articular facet by grooves (Figure 16a) as in Hesperornis. T h e inner and outer articular facets are about equal in size and are separated by a groove in the interarticular area in grebes. The inner articular facet is flat, oval, and directed posteromedially in Baptornis, and just below the inner articular facet is a deep roughened pit for the origin of M. plan- taris which appears to be divided into dorsal and ventral parts. The fibular crest extends about half way down the shaft and is deeply grooved along its FIGURE 15.?Left tibiotarsus of Baptornis advenus: a, pos? terior, b, lateral, c, anterior, and d, medial views, (X 1). NUMBER 27 55 a b d 56 SMITHSONIAN CONTRIBUTIONS TO PALEOBIOLOGY posterior margin, said groove crossing the outer border of the shaft just below the fibular crest. T h e foramen for the medullary artery lies in this groove. The distal attachment for the spine of the fibula is much smaller than in Hesperornis. The distal end of the tibiotarsus (Figures 14a, 15, 16fr) is slightly inflected medially, but not as much as in Gavia. In Hesperornis regalis and the grebes, the distal end is almost centered on the shaft. T h e internal and external condyles of the tibiotarsus are spread farther apart than in Hesperornis and the posterior crests are not as high. The tendinal groove is broad and terminates in a deep lateral pocket. The internal and external condyles are roughly parallel to each other and the anterior intercondylar sulcus is shallow (more so than in Hesperornis). Both the external and internal lig- amental prominences are very low. There is no supratendinal bridge, although a large ligamental attachment occurs above the medial side of the ex? ternal condyle. In F M N H 395 the high ascending process of the astragulus is still clearly discernable and the fusion of this tarsal element to the tibia evidently took place later in otogeny than in mod? ern birds. FIBULA (Table 6).?The fibula of Baptornis (Figure 14c) is most similar to that of Hesperornis. T h e head is large and rectangular. The shaft has two distinct ridges on its posterior proximal sur? face and the bicipital tubercle is large and elon? gate. The head is as in Hesperornis and is not undercut posteriorly as much as in loons. There is no tubercle for M. flexor perforatus digiti III as there is in loons, but instead there is a large tri? angular roughened area as in Hesperornis and grebes. TARSOMETATARSUS AND TOES (Tables 7,8).?As Shufeldt (1915:9) noted, the holotype tarsometa? tarsus designated by Marsh consists of two portions that are quite probably from different individuals, TABLE 6.?Measurements (mm) of the fibula of Baptornis TABLE 7.?Measurements (mm) of the tarsometatarsus of Baptornis Character Antero-posterior diameter proximal end Transverse diameter proximal end Greatest transverse shaft diameter Antero-posterior diameter at this point UNSM 20030 7 11 7.5 FMNH 395 6 9 7 KUVP 2290 8.5 11 - Character Length Proximal antero-posterior diameter Proximal width Distal antero-posterior diameter Distal width Tip trochlea II to distal end UNSM FMNH KUVP 20030 395 2290 84 (10) (17) 15 11.5 83 13.8 17.6 15.1 11.5 83E 13.5 18 16 12 E = restored length; ( ) specimens. measurements from crushed as indicated by the facts that the fracture lines of the two halves do not coincide and the proximal portion is from a juvenile, while the distal portion appears to be from an adult. If the two pieces had been from one individual, Shufeldt estimated that as much as a third of the shaft must be missing. At our request, the curators of the Division of Verte? brate Paleontology of the Yale Peabody Museum have agreed to retain YPM 1465 for the distal por? tion of this specimen, which we here designate as the lectotype. The proximal portion has been re? numbered as YPM 5768. KUVP 2290 represents a well-ossified individual in which the proximal and distal ends of a left tarsometatarsus are uncrushed, but in which the middle of the shaft is missing. YPM 5768 is from a young bird, and along with F M N H 395 (Figure 16/,g) and KUVP 16112 shows the lines of fusion between the metatarsal bones. T h e tarsometatarsus of UNSM 20030 is mature, but crushed. The tarsometatarsus of Baptornis is compressed laterally. The external cotyla is slightly larger than the internal one (Figure 16. ? -?? i ? ; ' ? -* . r \ ? - * ^ - - ^ ^ - ? , . ? ? * ? ? ^3 ^ Ht. ** ^fet^. ? - JES* ' FIGURE 1.?Holotype of Neanis schucherti (YPM 1233). The slab containing the actual bones, top to bottom: right radius, right ulna, right coracoid, furcula, left coracoid, and left humerus (actual length of proximal portion, 13.3 mm), left scapula. The sternum is to the left, and the approximate boundaries of the posterior notches of the left side of the sternum are outlined in ink. The position of the supposed spina externa is indicated by an arrow. that Brodkorb (1970:13) used to place Primobucco mcgrewi in the Piciformes and Bucconidae: " (1) proximal end inflected, so that entire caput humeri is medial to inner border of shaft (head of hu? merus more nearly in line with shaft in other fami? lies of Piciformes); (2) shaft more curved than in other piciform families; (3) deltoid crest long, bent near its mid-length at an angle of about 150 degrees (deltoid crest nearly parallel with shaft in other piciform families)." T h e other characters outlined by Brodkorb are not clearly visible in Neanis; how? ever, it is clear from the palmar view of the hu- 98 SMITHSONIAN CONTRIBUTIONS TO PALEOBIOLOGY M^M ft ? 'Mr?* / FIGURE 2.?The counterslab of the holotype of Neanis schucherti, containing the impressions of the bones of the slab in Figure 1 and some feather impressions. merus (Figure 1) that Neanis is not passerine, but piciform, and of living families is most similar to the Bucconidae, as are the two other species of Piciformes from the lower Eocene Green River Formation. The length of the humerus of Primobucco mcgrewi is 26.7 mm, and that of Primobucco kistneri was accurately estimated at 18-19 mm, as the entire outline of the bone was extant. In out? line, the humerus of Neanis schucherti is some? what similar to that of Primobucco kistneri, but the bones of the latter are so crushed that the com? parison is unsatisfactory; however, the two forms were of the same general size, which, as I stated of Primobucco kistneri (Feduccia, 1973:503), "would probably best approximate . . . some of the modern African barbets (Capitonidae) of the genus Pogo- niulus (including Viridobucco), which are ap? proximately 4-5 inches in total length." In the ab? sence of the evidence to the contrary, it seems best for the present to regard Neanis schucherti and Primobucco kistneri as distinct species; however, because of their general similarity in size, I recom? mend that P. kistneri be included in the genus Neanis, which has priority over Primobucco. Be? cause Primobucco mcgrewi is considerably larger than either Neanis schucherti or Neanis kistneri, I strongly recommend the retention of the genus Primobucco to represent the large lower Eocene piciform birds from the Green River Formation. NUMBER 27 99 Literature Cited Ames, P. L. 1971. The Morphology of the Syrinx in Passerine Birds. Bulletin of the Peabody Museum of Natural His? tory. 37:1-194. Brodkorb, P. 1965. New Taxa of Fossil Birds. Quarterly Journal of the Florida Academy of Sciences, 28(2): 197-198. 1970. An Eocene Puffbird from Wyoming. University of Wyoming Contributions to Geology, 9(1): 13-15. Feduccia, A. 1972. Variation in the Posterior Border of the Sternum in Some Tree-trunk Foraging Birds. Wilson Bulle? tin, 84(3):315-328. 1973. A New Eocene Zygodactyl Bird. Journal of Paleon? tology, 47(3):501-503, 1 figure, 1 plate. Heimerdinger, M. A., and P. L. Ames 1967. Variation in the Sternal Notches of Suboscine Pas? serine Birds. Postilla, 105:1-44. Olson, S. L. 1971. Taxonomic Comments on the Eurylaimidae. Ibis, 113(4):507-516. Sclater, P. H. 1874. On the Neotropical Species of the Family Pterop? tochidae. Ibis, series 3, 4:189-206. Shufeldt, R. W. 1913. Fossil Feathers and Some Heretofore Undescribed Fossil Birds. Journal of Geology, 21(7):628-652. The Eocene Zygodactyl Birds of North America (Aves: Piciformes) Alan Feduccia and Larry D. Martin ABSTRACT Recent discoveries of zygodactyl birds in the Eocene of Wyoming, along with reinterpretation of previously described taxa, show that these forms belong to an extinct family, affiliated with the Bucconidae, for which we here propose the name Primobucconidae. T h e genera Primobucco, Ne? anis, Uintornis, Botauroides, and a new genus, Eobucco, are assigned to this family, and three new species, Primobucco olsoni, Uintornis marionae, and Eobucco brodkorbi are described. Primobuc- conids appear to have been the dominant small perching birds of the Eocene of North America. Introduction Recent discoveries of piciform zygodactyl birds from the lower Eocene Green River Formation of Wyoming brought to light an entirely new element in the avifauna of the North American Tertiary. Brodkorb (1970a) described the first of these forms as a new genus and species of the Bucconidae, which is structurally the most primitive family of the Piciformes. This species, Primobucco mcgrewi, provided the earliest record of the order Piciformes and the only fossil record of the Bucconidae. In ad? dition to describing Primobucco mcgrewi, Brod? korb (1970a) suggested that Uintornis lucaris Marsh (1872), from a much higher level in the Eocene than P mcgrewi, might also be referable to Alan Feduccia, Department of Zoology, University of North Carolina, Chapel Hill, North Carolina, 27514. Larry D. Mar? tin, Museum of Natural History and Department of Sys- tematics and Ecology, University of Kansas, Lawrence, Kansas, 66045. the Bucconidae. Later, Feduccia (1973) described a new zygodactyl bird, Primobucco kistneri, from the same formation as P. mcgrewi. While P. mcgrewi was based on a right wing, the type of P. kistneri included much of the skeleton on a slab. Although the bones were poorly preserved, the zygodactyl condition of the toes could be clearly discerned for the first time in any known fossil. Few useful osteological characters were present in this fossil, but by using ratios of the hindlimb ele? ments it was at least possible to show that P. kistneri was a "perching" piciform bird, closely re? sembling the Bucconidae and Capitonidae in proportions. Being from the same approximate horizon and locality as P. mcgrewi, it seemed rea? sonable to assume that the two were related, al? though P. mcgrewi was larger than the modern bucconids Notharchus tectus or Malacoptila pana? mensis (Brodkorb, 1970a: 14), whereas P. kistneri was much smaller, being approximately the size of some of the modern African capitonids of the ge? nus Pogoniulus, which are about 100-130 mm long. Feduccia (pp. 95-99, herein) examined the type of Neanis schucherti (Shufeldt, 1913), also from the lower Eocene of Wyoming, which was origi? nally described as belonging to the Rhinocryptidae, thus supposedly representing the earliest record of the order Passeriformes. He found, however, that this species is not a passerine, but a piciform, prob? ably congeneric with P. kistneri. Because both these species are much smaller than P. mcgreivi, P. kistneri was removed to the genus Neanis, and the genus Primobucco was reserved for larger lower Eocene forms the size of P. mcgrewi. T h e problematical genus Uintornis was origi? nally affiliated with the woodpeckers (Picidae) by Marsh (1872). Shufeldt (1915:51) stated emphat- 101 102 SMITHSONIAN CONTRIBUTIONS TO PALEOBIOLOGY ically that this assignment was erroneous, but left the question of the true affinities of the genus un? settled. Cracraft examined the type and agreed with Shufeldt that it was not from a woodpecker, suggesting instead that it belonged with the Cuculi- formes (Cracraft and Morony, 1969:6). On Cra- craft's suggestion, Brodkorb (1970b; 1971) placed Uintornis in the Cuculidae. Our present studies of the type of Uintornis lucaris show that it is not a cuculid and that Brodkorb's (1970a) original as? signment of it to the Bucconidae was more nearly correct. We found three other tarsometatarsi, also from middle Eocene deposits in North America, to be affiliated with Uintornis at the family level. One of these was originally described by Shufeldt (1915) as a new genus and species of heron, Botauroides parvus; the second represents an undescribed spe? cies of Uintornis; while the last represents a new genus. Two species of piciform birds from the Miocene of Europe have been placed in an extinct family Zygodactylidae (Brodkorb, 1971), based on the ge? nus Zygodactylus (Ballman, 1969a; 1969b). These forms are distinctly different from the above spe? cies and further study of them will be necessary in order to clarify their affinities with other groups of modern and Tertiary zygodactyl birds. Mean? while, the morphology of the Eocene forms pre? cludes their assignment to any known family of the Piciformes and the erection of a new family is therefore made necessary. ACKNOWLEDGMENTS.?We are greatly indebted to S. W. Shannon of the Geological Survey of Ala? bama for bringing to our attention the type of Primobucco olsoni and placing it at our disposal for study. P. O. McGrew of the University of Wyo? ming, Department of Geology, kindly lent the types of Primobucco mcgrewi and Neanis kistneri. Skele? tons of modern species were made available through the courtesy of Pierce Brodkorb (Univer? sity of Florida), R. W. Storer (University of Michi? gan Museum of Zoology), and R. L. Zusi (National Museum of Natural History, Smithsonian Institu? tion). C. B. Schultz made the University of Nebraska specimen available. D. Adams and D. Bennett rendered the illustrations. Abbreviations are as follows: Geological Survey of Alabama Type Collection (GSATC), University of Kansas Mu? seum of Natural History (KUVP), University of Nebraska State Museum (UNSM), University of Wyoming Geological Museum (UWGM), and Yale Peabody Museum (YPM). Order PICIFORMES Suborder GALBULAE PRIMOBUCCONIDAE, new family INCLUDED GENERA.?Primobucco, Neanis, Uin? tornis, Botauroides, Eobucco. DIAGNOSIS.?Small perching birds with the fol? lowing combination of characters: (1) humerus (Figure la) with shaft curved, the head inflected medially, and the deltoid crest low, slightly rounded and proximally located; (2) radius and ulna (Fig? ure la) slender and elongate; (3) metacarpals II FIGURE 1.?a, Restorat ion of the r igh t wing of Primobucco olsoni, pa lmar view. Pa lmar views of r ight humer i : b, Cheli- doptera tenebrosa (Bucconidae); c, Megalaima lineata (Capi- tonidae); d, Tauraco sp. (Musophagidae); e, Tapera naevia (Cuculidae). NUMBER 27 103 and III (Figure la) nearly parallel to each other, with only a narrow intermetacarpal space; (4) phalanx 1 digit II of manus (Figure la) broader proximally than in most other Piciformes; (5) tarsometatarsus (Figure 2e, f) relatively short, broad, and flat; (6) hypotarsus with a square lat? eral block of bone and a low ridge leading distally from it (Figure 6), probably with only a single tendinal canal (not clearly determinable in any known specimen); (7) papilla for tibialis anticus on the extreme internal margin of the tarsometa? tarsus (Figure 2e, f); (8) tarsometatarsus with a single proximal foramen (Figure 6); (9) distal end of tarsometatarsus flared, with large intertrochlear spaces and trochleae lying in the same anterior- posterior plane (Figures 2e,f,k; 5; 6); (10) middle trochlea the most distad, with the inner and outer trochleae about subequal (Figures 2e,f; 5; 6); (11) facet for metatarsal I entirely medial (Figures 5, 6); (12) inner trochlea grooved distally and pos? teriorly, middle trochlea deeply grooved (Figures 5, 6); (13) outer trochlea inflected inwards, with- ] ! FIGURE 2.?Proximal views of left tarsometatarsi: a, Notharcus macrorhynchos (Bucconidae); b, Megalaima lineata (Capitonidae); c, Tauraco sp. (Musophagidae); d, Piaya cayana (Cuculidae). Restoration of the distal end of the left tibiotarsus and tarsometatarsus: e, Primobucco olsoni. Anterior (/-/) and distal (k-o) views of left tarsometatarsi: /, k, Eobucco brodkorbi (Primobuc- conidae); g, I, Notharcus macrorhynchos (Bucconidae); h, 'm, Megalaima lineata (Capitonidae); i, n, Tauraco sp. (Musophagidae); /', o, Piaya cayana (Cuculidae). 104 SMITHSONIAN CONTRIBUTIONS TO PALEOBIOLOGY out a well-developed sehnenhalter, but with a dis? tinct groove separating the posterior portion of the trochlea from the remainder. REMARKS.?Characters 1, 6, and 13 of the diag? nosis eliminate all families of the Piciformes ex? cept the Bucconidae. In the other piciformes, the bill is long (except in indicatorids and capitonids), the shaft of the humerus tends to be straight with the deltoid crest parallel to it (Figure lc), there are two or more hypotarsal canals arranged one be? hind the other (Figure 2b), and the sehnenhalter is well developed (Figure 2m). The fossils tend to be bucconid-like in characters 1, 2, 3, 5, 6, 7, 8, and 13. They differ from the Bucconidae, however, in having a shorter mandibular symphysis, and in characters 4, and 9 through 12. The bucconids and the other piciforms differ from the Primobucconi- dae in that phalanx 1 digit II of the manus is narrower, especially at its proximal end; the inner and middle trochleae of the tarsometatarsus are placed closer together and the outer trochlea is elevated; the anterior face of the middle trochlea is not deeply grooved; and the facet for the first metatarsal is posteriorly situated. Because Uintornis was suggested as being culculi- form (Cracraft and Morony, 1969), we have com? pared all members of the Primobucconidae with nine genera of Cuculidae and three genera of Musophagidae. The Primbucconidae differ from both of these families in all but character 10 in the above diagnosis. The musophagids and cuculids differ from the Primobucconidae in that the ulna is short, strongly curved, and has large feather papil? lae; metacarpal III is strongly curved so that there is a large intermetacarpal space; the supratendinal bridge is much above the proximal margin of the condyles of the tibiotarsus; the tarsometatarsus is elongate (Figure 2i,f); the inner and middle trochleae are close to each other, and the outer trochlea is elevated and inflected inwards, with no separation of the posterior portion from the rest of the trochlea (Figure 2n,o); the facet for metatarsal I is located posteriorly and the inner trochlea is not prominently grooved. The anterior face of the tar? sometatarsus is often deeply excavated in cuculi- forms and there are usually two proximal foramina. The cuculids always have two large enclosed hypo? tarsal canals (Figure 2d), a feature that is certainly absent in the only primobucconid in which it can be checked. Also, musophagids have a very triangu? lar and distally situated deltoid crest (Figure Id). Clearly the Primobucconidae belong in the Piciformes and are most closely related to the Buc? conidae. We can find no substantive evidence for a relationship between Uintornis (or any of the other forms of Primobucconidae) and any group of the Cuculiformes. The family Primobucconidae includes five gen? era. T h e species of two of these genera, Primobucco and Neanis, are preserved as crushed specimens on slabs and represent medium-sized and small forms, respectively, of lower Eocene age. Three genera, Uintornis, Botauroides, and Eobucco, are medium to large in size and are middle Eocene in age; all are represented by fairly well-preserved tarsometa? tarsi only. Obviously, distinguishing the lower from the middle Eocene forms is difficult because the material is not strictly comparable. Neverthe? less, size differences and such characters of the tarsometatarsus as can be discerned in the lower Eocene genera will permit them to be distinguished from most, if not all, of the middle Eocene forms. For this reason, and because of the time element involved, we believe it is best to recognize five genera in the Primobucconidae. Primobucco Brodkorb, 1970a TYPE-SPECIES.?Primobucco mcgrewi Brodkorb, 1970a. INCLUDED SPECIES.?P. mcgrewi, P. olsoni. AMENDED DIAGNOSIS.?Medium-sized primobuc- conids, larger than Neanis and probably smaller than Uintornis, Botauroides, or Eobucco. Primobucco mcgrewi Brodkorb, 1970a HOLOTYPE.?Right wing, U W G M 3255. TYPE-LOCALITY AND HORIZON.?From fish quar? ries in SE 14 of Sec 18, T21N, R117W, near Fos? sil, Lincoln County, Wyoming; lower beds of Green River Formation, lower Eocene (Late Wasatchian) (Brodkorb, 1970a). Primobucco olsoni, new species FIGURES \a, 3, 4 HOLOTYPE.?Two slabs containing a nearly com? plete skeletal impression and counterimpression, NUMBER 27 105 Geological Survey of Alabama Type Collection, GSATC 217 (Figures 3, 4). TYPE-LOCALITY AND HORIZON.?The "first bluff" north of US Highway 30 north, across from Nug? get, Lincoln County, Wyoming; Green River For? mation, lower Eocene. Collected by Mr. George Moravec. DIAGNOSIS.?Smaller than Primobucco mcgrewi but larger than Neanis. Wing more slender and humerus longer than in Primobucco mcgrewi. Middle trochlea of tarsometatarsus extending far? ther distally than the other trochleae. DESCRIPTION.?Skeleton preserved on two slabs with numerous feather impressions; mandible broad with a short symphysis; humerus with a low, gently curved deltoid crest almost parallel to shaft (Figure la); head of humerus inflected me? dially; radius and ulna slender, straight, and elon? gate, the ulna with no evidence of feather papil? lae; carpometacarpus long and slender with a large, straight process for metacarpal I and a nar? row intermetcarpal space; phalanx 1 digit II of the manus broad (narrower proximally in most bucconids); tibiotarsus short and robust with the supratendinal bridge straight, lying just above the condyles; tarsometatarsus broad, short, and flat with a high intercotylar prominence, anterior face of shaft with a low medial ridge, a single medial &? s . 1 - J FIGURE 3.?Holotype slab of Primobucco olsoni, new species (GSATC 217), viewed ventrally. (a.t. = anterior toes, co = coracoid, cm = carpometacarpus, d = digit II, h = humerus, m = mandibular ramus, p.t. = posterior toes, r.u. = radius and ulna, tm = tarsometatarsus, tt = tibiotarsus) 106 SMITHSONIAN CONTRIBUTIONS TO PALEOBIOLOGY FICURE 4.?Holotype counterslab of Primobucco olsoni, new species, viewed dorsally. (Abbreviations as in Figure 3.) proximal foramen, the papilla for tibialis anticus along the medial edge, the facet for metatarsal I situated medially, the middle trochlea situated dis? tally, and the trochleae deeply grooved. Compared to Primobucco mcgrewi the humerus of P. olsoni is longer (28.8 vs. 26.7 mm), the shaft more slender (least width c. 2.2 vs. 3.0 mm), the proximal width greater (c. 7.5 vs. 6.7 mm), the ulna shorter (c. 32.0 vs. 34.2 mm), and phalanx 1 digit II of manus shorter (c 6.7 vs. 7.0 mm). T h e approxi? mate length of the coracoid is c. 15.0 mm and that of the mandibular ramus c. 34.5 mm. T h e esti? mated toe lengths measured (in mm) through the arc are: digit I, 11.0; digit II, 16.4; digit III, 18.8; and digit IV, 13.3. Equivalent estimates of the toe arcs for Neanis kistneri are 6.8, 7.4, 8.6, and 8.2, respectively. T h e chord of the left wing of P. olsoni is estimated at 92 mm; of the species of Buc? conidae listed in Ridgway (1914), the Barred Puffbird, Nystalus radiatus, is the nearest in size, with the wing chord of males averaging about 92 mm. ETYMOLOGY.?The specific name is in honor of Storrs L. Olson for his contributions to avian paleontology. REMARKS.?No accurate measurements of the tibiotarsus were possible but by comparing the two sides we were able to estimate the total length of the tibiotarsus very roughly as 28.5 ( ? 3) mm. The tarsometatarsus measures c. 15.5 mm, giving a ratio of tarsometatarsus to tibiotarsus of approxi? mately 0.54. This rules out an affinity with the NUMBER 27 107 Picidae (average ratio of 8 species, 0.67) or the Cuculidae (average of 7 species, 0.69). T h e same ratio for Neanis kistneri is 0.56; the average for 6 species of Bucconidae, 0.58; 3 species of Galbulidae, 0.51; five species of Capitonidae, 0.58; and 2 spe? cies of Indicatoridae, 0.59 (Feduccia, 1973). These ratios indicate only that the fossil does not belong to either the Cuculidae or the Picidae, but is a "perching" piciform bird. In woodpeckers, the dif? ferent ratio results from the tibiotarsus being pro? portionately reduced. Comparative measurements of bucconids are given in Brodkorb (1970a). The holotype of Primobucco olsoni is especially important because it permits us to associate the skeleton of Primobucco with those primobucconids known only from the tarsometatarsus. Features in which Primobucco resembles Eobucco and Uintor? nis are the short, broad tarsometatarsus with a high intercotylar prominence, the single lateral proximal foramen, the small and very medially situated tubercle for the tibialis anticus, and the medially situated facet for metatarsal I. Neanis Brodkorb, 1965 SYNONYM.?Hebe Shufeldt, 1913 (preoccupied). TYPE-SPECIES.?Hebe schucherti Shufeldt, 1913. INCLUDED SPECIES.?N. schucherti, N. kistneri. AMENDED DIAGNOSIS.?Wing relatively shorter than in Primobucco; tarsometatarsus with large hypotarsus. REMARKS.?Better preserved material is needed for a full diagnosis of the very small zygodactyl birds referred to Neanis. Neanis schucherti (Shufeldt, 1913) HOLOTYPE.?YPM 1233, partial skeleton on a slab and impression on counterslab. TYPE-LOCALITY AND HORIZON.?Fish cut of the railroad, 8 km west of Green River City, Wyoming; Green River Formation, lower Eocene. Neanis kistneri (Feduccia, 1973) HOLOTYPE.?UWGM 3196, partial skeleton on a slab. TYPE-LOCALITY AND HORIZON.?N i/2, N W 14, Sec 6, T23N, R104W, Sweetwater County, Wyom? ing; Tip ton Tongue Member of the Green River Formation, lower Eocene (Wasatchian). AMENDED DIAGNOSIS.?Smaller than N. schu? cherti or any of the other primobucconids. Uintornis Marsh, 1872 TYPE-SPECIES.?Uintornis lucaris Marsh, 1872. INCLUDED SPECIES.?U. lucaris, U. marionae. AMENDED DIAGNOSIS.?Zygodactyl birds with the outer trochlea of the tarsometatarsus not as strongly rotated as in other primobucconids; mid? dle trochlea situated distally; distal foramen located above the outer trochlea. Uintornis lucaris Marsh, 1872 HOLOTYPE.?YPM 617, distal end of right tarso? metatarsus (Figure 5/,g). f\_/ l cm FIGURE 5.?Tarsometatarsi of Uintornis and Botauroides: a-d, holotype partial left tarsometatarsus of Uintornis marionae, new species (KUVP 26906), anterior, posterior, medial, and distal views; e, holotype, partial left tarsometatarsus of Botauroides parvus (YPM 1030), anterior view; f-g, holotype partial right tarsometatarsus of Uintornis lucaris (YPM 617), anterior and posterior views. 108 SMITHSONIAN CONTRIBUTIONS TO PALEOBIOLOGY TYPE-LOCALITY AND HORIZON.?Henry's Fork, Sweetwater County, Wyoming; Bridger Formation, middle Eocene. AMENDED DIAGNOSIS.?Outer trochlea of tarsome? tatarsus inflected inwards but with inner and outer trochlear ridges not widely separated; middle trochlea located much farther distally than the others and distal foramen located more proximad. DESCRIPTION.?Shaft of tarsometatarsus broad and flat; inner extensor grooves deep; distal foramen more proximal than the outer trochlea; distal end expanded with wide intertrochlear notches; trochleae deeply grooved; inner trochlea small, smooth anteriorly and grooved posteriorly, with a small medially directed posterior flange; middle trochlea deeply grooved, with high, thick, trochlear ridges, the inner trochlear ridge distal to the outer and with a short, thick neck; outer trochlea large, at the same level as the inner troch? lea and inflected medially; outer trochlea grooved, with the outer ridge produced posteriorly as a flange or incipient sehnenhalter; facet for metatarsal I medially situated. Measurements (in mm) of type: width of distal end, 4.77; width of shaft at distal foramen, 3.3; depth and width of inner trochlea, 1.36 and 1.27; depth and width of middle trochlea, 2.00 and 1.90; depth of outer trochlea 2.90. Uintornis marionae, new species FIGURE 5a-d HOLOTYPE.?KUVP 26906, distal end of right tarsometatarsus lacking outer trochlea (Figure 5a-d). TYPE-LOCALITY AND HORIZON.?Sage Creek, Sweet? water County, Wyoming; Bridger Formation, mid? dle Eocene. DIAGNOSIS.?Resembles Uintornis and differs from Botauroides in having a more slender shaft, a small inner trochlea, and a distinct groove proximal to the outer trochlea. Differs from Uintornis lucaris in being about 25 percent larger, and in having the facet for metatarsal I less deeply impressed and the outer ridge of the outer trochlea more medially inclined and elongated. DESCRIPTION.?Tarsometatarsus broad and flat; distal foramen lying proximal to outer trochlea in anterior view and not visible in posterior view; facet for metatarsal I situated laterally; inner trochlea grooved posteriorly and smooth anteri? orly; intertrochlear spaces wide; middle trochlea deeply grooved and situated distally; trochleae not arched. Measurements (in mm) of type: width of shaft at distal foramen, 4.18; depth and width of inner trochlea, 1.83 and 1.34; depth and width of middle trochlea, 2.25 and 2.02. ETYMOLOGY.?Named for Marion A. Jenkinson, who has often assisted us in our work on fossil birds. REMARKS.?The size difference and various quali? tative features of the specimen separate it from Uintornis lucaris. After Eobucco, described later in this paper, it is the largest known member of the Primobucconidae. Uintornis seems to be the least specialized genus of the family in terms of toe rotation. Botauroides Shufeldt, 1915 TYPE-SPECIES.?Botauroides parvus Shufeldt, 1915. INCLUDED SPECIES.?B. parvus. AMENDED DIAGNOSIS.?Botauroides differs from Uintornis in having a proportionately wider shaft, the notch for the facet of metatarsal 1 shallower and slightly more posterior, the inner trochlea at about the same level as the middle trochlea, and outer trochlea not as elevated. T h e inner ridge of the outer trochlea is slightly more rotated and does not project as far anteriorly as it does in Uintornis. The outer trochlea is proportionately smaller and the medial ridge of the middle trochlea swings farther medially. Uintornis has a shallow groove just proximal to the outer trochlea, and the inner trochlea is relatively smaller than in Botauroides. Botauroides parvus Shufeldt, 1915 HOLOTYPE.?YPM 1030, distal end of left tarso? metatarsus (Figure be). TYPE-LOCALITY AND HORIZON.?Spanish John Meadow, Wyoming; Bridger Formation, middle Eocene. DIAGNOSIS.?As for the genus. DESCRIPTION.?Shaft very broad and flat, not ex? panded distally; distal foramen situated far proxi? mally; inner trochlea larger and grooved posteri? orly; inner and middle trochleae at same level; NUMBER 27 109 outer trochlea relatively small, rotated medially and not very elevated; trochleae not arched. REMARKS.?Cracraft (pers. comm.) directed our attention to the similarities between Botauroides and Uintornis. Shufeldt (1915), with his uncanny ability to err, had referred it to the Ardeidae, where it appears in Brodkorb's (1963) catalog. Eobucco, new genus TYPE-SPECIES.?Eobucco brodkorbi, new species. DIAGNOSIS.?Largest known primobucconid; re? sembles Uintornis and differs from Botauroides in having the facet for metatarsal I deeply impressed and the middle trochlea located farther distally. Differs from Uintornis in having the ridges of the middle trochlea not extending as far proximally on the anterior side; in having the outer ridge of the outer trochlea inclined more medially and elongated until it extends past the outer ridge of the middle trochlea (it does not reach this trochlea in Uintornis); in having the outer ridge of the inner trochlea extending posteriorly as a distinct flange; and in the far distal position of the distal foramen. Eobucco brodkorbi, new species FIGURE 6 HOLOTYPE.?UNSM 20046 (Figure 6), left tarso? metatarsus. TYPE-LOCALITY AND HORIZON.?56 km north of Green River, Sweetwater County, Wyoming; Bridger Formation, middle Eocene. DIAGNOSIS.?As for the genus. DESCRIPTION.?Shaft of tarsometatarsus short, broad, and flattened; intercotylar prominence high and large; hypotarsus damaged but with a large lateral square of bone, which may have in? cluded a closed canal (the two closed canals, such as found in cuculids, could not have been present); a shallow groove rather than a ridge leads distally from the hypotarsus; anterior face of shaft grooved, with a high lateral ridge present; medial edge of shaft thin; a single large proximal foramen present near the midline; tubercle for tibialis anticus very small and distally situated along the medial edge of the shaft; facet for metatarsal I high and deeply impressed into the medial side of the shaft; distal foramen small, level with the outer trochlea; trochleae widely spread, not arched; inner trochlea relatively large, anterior face smooth, posterior face grooved; proximal part of the outer rim of the outer trochlea produced into a large posterior flange; middle trochlea large with high trochlear ridges diverging posteriorly; middle trochlea more distal than other trochleae; large outer trochlea at the same level as the inner trochlea; outer trochlea rotated medially with its elongate outer ridge ex? tending medially past the outer r im of the middle trochlea; outer trochlea grooved. Measurements (in mm) of type: total length, 26.95; width of proximal end, 6.75; width of distal end, 6.00; depth and width of the inner trochlea, 1.36 and 1.27; depth and width of middle trochlea, 2.00 and 1.90; depth and width of outer trochlea, 2.90 and 1.80. ETYMOLOGY.?Named for Pierce Brodkorb, who l em FICURE 6.?Holotype left tarsometatarsus of Eobucco brod? korbi, new genus and species (UNSM 20046): a, anterior view; b, posterior view; c, lateral view; d, distal view; e, proximal view. 110 SMITHSONIAN CONTRIBUTIONS TO PALEOBIOLOGY was the first to recognize the true affinity of the primobucconids. REMARKS.?This is the largest and most advanced of the known primobucconids. It shares with Uin? tornis the distal position of the middle trochlea but has the outer trochlea much larger and more me? dially rotated. The single proximal foramen is re? markable for its large size and central position, thereby resembling the proximal foramen in Galbula. The medial side of the shaft is deeply in? dented under the internal cotyla where it is re? duced to a thin blade. The tubercle for the tibialis anticus is extremely reduced. Eobucco possesses a combination of primitive and specialized char? acters that probably preclude its having given rise to any modern group of piciforms. Conclusion The allocation of Neanis schucherti, Uintornis lucaris, and Botauroides parvus to the Piciformes, and the description of the new forms Primobucco olsoni, Uintornis marionae, and Eobucco brod? korbi, brings the total number of species of North American Eocene zygodactyl birds to eight: two very small forms, Neanis schucherti and Neanis kistneri; two medium-size forms, Primobucco mcgrewi and Primobucco olsoni; two large forms, Eobucco brodkorbi and Uintornis marionae, and two others, Uintornis lucaris and Botauroides par? vus, slightly smaller than the last two. The order Piciformes probably arose in the New World and its forms occupied the "perching" ar? boreal adaptive zone in the early Tertiary of North America when tropical and subtropical cli? mates predominated. Later, the order spread to the Old World where the Miocene Zygodactylidae and the modern families Picidae, Capitonidae, and Indicatoridae are represented, the last named being the only modern piciform family not found in the New World. Probably through climatic change and competition with more advanced land birds, e.g., passerines, the piciforms retreated mainly to tropical zones of the New and Old Worlds. The most primitive living piciform families, the Bucconidae and Galbulidae, are presently confined to the New World tropics. T h e Bucconidae are structurally closest to the Eocene family Primobucconidae. The preponderance of evidence now indicates that the typical "perching" birds of the early Terti? ary of North America were primitive piciforms, rather than passerine birds. Thus, it was probably not until the mid-Tertiary that the passerines took over in North America as the predominant "perch? ing" group. Literature Cited Ballmann, P. 1969a. Les oiseaux miocenes de La Grive-Saint-Alban (Isere). Geobios 2:157-204. 1969b. Die Vogel aus der altburdigalen Spaltenfullung von Wintershof (West) bei Eichstatt in Bayern. Zitteliana 1:5-60. Brodkorb, P. 1963. Catalogue of Fossil Birds, Part 1 (Archaeopterygi- formes through Ardeiformes). Bulletin of the Flor? ida State Museum, Biological Sciences, 7(4): 180-293. 1965. New Taxa of Fossil Birds. Quarterly Journal of the Florida Academy of Science, 28:197-198. 1970a. An Eocene Puffbird from Wyoming. University of Wyoming Contributions to Geology, 9(1): 13-15, 1 figure. 1970b. The Paleospecies of Woodpeckers. Quarterly Jour? nal of the Florida Academy of Sciences, 33(2):132- 136, 1 figure. 1971. Catalogue of Fossil Birds, Part 4 (Columbiformes through Piciformes). Bulletin of the Florida State Museum, Biological Sciences, 15(4): 163-226. Cracraft, J., and J. J. Morony, Jr. 1969. A New Pliocene Woodpecker, with Comments on the Fossil Picidae. American Museum Novitates, 2400:1-8, 1 figure. Feduccia, A. 1973. A New Eocene Zygodactyl Bird. Journal of Paleon? tology, 47(3):501-503, 1 figure, 1 plate. Marsh, O. C. 1872. Notice of Some New Tertiary and Post-Tertiary Birds. American Journal of Science, 4(3):256-262. Ridgway, R. 1914. The Birds of North and Middle America. Bulletin of the United States National Museum, 50 (6): 1-882. Shufeldt, R. W. 1913. Fossil Feathers and Some Heretofore Undescribed Fossil Birds. Journal of Geology, 21:628-652, 12 figures. 1915. Fossil Birds in the Marsh Collection of Yale Uni? versity. Transactions of the Connecticut Academy of Arts and Sciences, 19:1-110, 15 plates. Oligocene Fossils Bearing on the Origins of the Todidae and the Momotidae (Aves: Coraciiformes) Storrs L. Olson ABSTRACT A new genus and species of tody, Palaeotodus emryi, is described from the "middle" Oligocene (Orellan land mammal stage) of Wyoming, providing the first record of the modern family Todidae out? side the West Indies. T h e fossil bird Protornis glarniensis from the lower Oligocene of Switzer? land is removed from the Alcedinidae to the Momotidae to provide the first occurrence of the latter family outside the New World. T h e Todidae and Momotidae appear to be more closely related to each other than either is to any other family of Coraciiformes. T h e Momotidae were evi? dently derived from the Old World. T h e Todidae appear to have been derived from a momotid-like ancestor in the Oligocene or earlier. T h e present distribution of these two families in the New World tropics is relictual. T h e Coraciiformes ap? pear to have been one of the prevalent groups of small land birds in the Oligocene. Introduction The five modern species of todies (Todidae), endemic to the Greater Antilles, are among the most intriguing birds of the West Indies. The Mo? motidae of Central and South America and the Todidae are the only families of Coraciiformes confined to the New World. Apart from late Pleis? tocene remains of modern species, there has hitherto been no fossil record of either family. Storrs L. Olson, Department of Vertebrate Zoology, National Museum of Natural History, Smithsonian Institution, Wash? ington, D.C. 20560. Now, a recently discovered fossil and a new inter? pretation of one of the first fossil birds to be de? scribed, provide us with increased information bearing on the evolution and geographic origins of both the Todidae and the Momotidae. ACKNOWLEDGMENTS.?I am indebted to Robert J. Emry for calling the Wyoming specimen to my at? tention, permitting me to work on it, and pro? viding much information and assistance. The manuscript has had the benefit of his comments and those of John Farrand, Jr., Alan Feduccia, and Pierce Brodkorb. Robert W. Storer (University of Michigan Museum of Zoology) kindly lent me a skeleton of Hylomanes for study, and casts of Swiss fossils were generously lent by Malcolm C. McKenna (American Museum of Natural His? tory). I am grateful to L. B. Isham for his skillful illustrations accompanying this paper and to Anne Curtis for rendering Figure 3. An Oligocene Tody from Wyoming In June of 1972, Dr. Robert J. Emry of the Smithsonian Institution collected several blocks of matrix containing great concentrations of bones of small vertebrates from a deposit of Orellan age ("middle" Oligocene) in east-central Wyoming. Present in these samples are the abundant re? mains of at least two species of squirrels, various smaller rodents, small marsupials, and insectivores. T h a t this great concentration of bone may be at? tributed to the work of owls is virtually certain since the blocks also contain the beautifully pre? served skeletons of at least four small owls, possibly of two species. I l l 112 SMITHSONIAN CONTRIBUTIONS TO PALEOBIOLOGY On the surface of one of these blocks, Dr. Emry noticed the bill of a small bird and later found a crushed avian cranium that fit perfectly with the bill. After the two portions had been reunited, an incomplete avian humerus was found attached to the lower surface of the skull. There is no rea? son to believe that the humerus and skull are not from the same individual. Were they not, the owl that cast the pellet containing these remains would have had to eat two different birds at the same time, since it is rare for elements from a single prey item to be found in two successive pellets (Rac- zyhski and Ruprecht, 1974). This would seem un? likely, particularly in view of the absence of birds other than owls in the remainder of the samples. The distinctively shaped, flattened bill of the fossil was immediately reminiscent of the Todidae, but since bills of similar shape have evolved inde? pendently in several groups of birds, many of them passerines, identification was made cautiously. After careful comparisons, I concluded that this specimen is indeed referable to the family Todidae. Palaeotodus, new genus TYPE.?Palaeotodus emryi, new species. DIAGNOSIS.?Similar to modern Todus but with different proportions, the wing apparently being better developed. Bill proportionately shorter and broader, not as pointed as in Todus. Mandibular rami not as flattened, the anterior portions grooved, so as to form a distinct dorsal shelf. Three ridges on the ventral side of the interorbital bridge separate, rather than coalesced as in Todus. ETYMOLOGY.?Greek, palaeos, ancient, plus To? dus, the genus of modern todies. See Newton (1896:970, footnote) for the etymology of Todus. Palaeotodus emryi, new species FIGURE 1 HOLOTYPE.?Incomplete and partially crushed skull with most of the anterior portions of the ros? trum intact, including the mandibular symphysis and parts of both rami; crushed posterior portion of cranium with ventral surface of interorbital bridge well preserved; much of the rest of the skull crushed, jumbled, and displaced ventroanteriorly. Vertebrate Paleontological Collections of the Na? tional Museum of Natural History, Smithsonian Institution, USNM 205608. Collected in N W 1/4, SE 1/4, Sec. 27, T32N, R71W, about 5.6 km SSE of Douglas, Converse County, Wyoming (42?42'55"N; 105?21T5"W) on 12 June 1972 by Robert J. Emry (Field No. WYO. 72-246) and Leroy Glenn. HORIZON.?Brule Formation, Orellan land- mammal stage, "middle" Oligocene. PARATYPE.?Somewhat distorted right humerus with the shaft crushed and lacking the distal end; same number and data as the holotype. MEASUREMENTS.?Overall length of skull as pre? served 34.5 mm, length of bill from anterior of nos? tril 10.0, length of mandibular symphysis 7.8, width of mandible at beginning of symphysis 5.6, width of mandibular ramus 1.7, proximal width of hu? merus 6.7. ETYMOLOGY.?After Dr. Robert J. Emry, the col? lector, in recognition of his significant contribu? tions to our knowledge of the Oligocene fauna of North America. DESCRIPTION.?Bill flat, broad, nearly spatulate, with a broader more rounded tip than in Todus. Internarial bar long, slender, terete, and somewhat heavier than in Todus, continued out the rostrum as a slightly elevated ridge. Mandible flattened, the symphysis shorter and broader than in Todus; mandibular rami deeper than in Todus, grooved anteriorly to form a dorsal shelf. Ventral surface of interorbital bridge with three ridges, the middle one terminating in a pointed process (tip broken off in the type), the outer ones flaring laterally to form the edges of the huge anterior cranial fenes? tra. The condition in Todus is essentially similar, but the three ridges are not as distinct anteriorly and coalesce to form a narrower, deeper interor? bital bridge. T h e middle process in Todus is a FIGURE 1.?Skull (holotype) and humerus (paratype) of Palaeotodus emryi, new genus and species (USNM 205608), compared with the same elements of Todus subulatus (USNM 292589): a, dorsal view of skull of P. emryi; b, dorsal view of skull of T. subulatus; c, lateral view of skull of P. emryi; d, ventral view of mandible of P. emryi; e, f, cutaway views of ventral side of interorbital bridge and dor? sal part of anterior cranial fenestra of T. subulatus; g, h, same views of P. emryi; i, anconal view of humerus of P. emryi; j , proximal end of humerus of P. emryi, viewed with distal portion tilted further upward; k, proximal view of same; /', anconal view of humerus of T. subulatus. (All figures approximately X 3.) NUMBER 27 113 114 SMITHSONIAN CONTRIBUTIONS TO PALEOBIOLOGY point of attachment for a narrow ligament that joins with similar ligaments from the parasphenoid rostrum and the lateral edges of the cranial fenes? tra to form a tenuous cross holding the anterior part of the brain in place. The humerus of Palaeo? todus is similar to that of Todus, but is much larger; the internal tuberosity is heavier and much less lateromedially elongate; and the ligamental furrow and the scar on the external tuberosity are both considerably deeper. REMARKS.?Few nonpasserine landbirds have the bill anywhere near as flattened as in Todus and Paleotodus. Those with the most flattened bills are Electron, Hylomanes, and Aspatha (Momotidae), Jacamarops (Galbulidae), and Myioceyx (Alce- dinidae). In all of these forms the bill is deeper and the internarial bar broader and shorter than in either of the two genera of Todidae. The bony structure of the bill in passerines, as for example in Todirostrum (Tyrannidae), is quite different from that of Todus and Palaeotodus, being deeper and more arched, with a more troughlike mandible and a shorter, wider, and less terete internarial bar. Palaeotodus agrees with Todus and differs con? spicuously from the Momotidae, Alcedinidae, Gal? bulidae, and indeed from all of the rest of the Coraciiformes and Piciformes, in having the ante? rior wall of the cranium and the interorbital sep? tum unossified. In the Momotidae, Alcedinidae, and Galbulidae the interorbital septum is partially or very heavily ossified. The anterior wall of the cranium is ossified in all of these families, whereas in Todus and Palaeotodus there is a great, open fenestra. The humerus of Palaeotodus is broken and dis? torted, with the head crushed down distally relative to the internal and external tuberosities. Although in Todus there is slightly more of a depression be? neath the head than in other Coraciiformes, the humerus can in no sense be regarded as having a double fossa, as stated by Bock (1962), and has a single pneumatic opening beneath the internal tuberosity. Palaeotodus is similar to Todus in this respect. The humerus of Palaeotodus differs from that of the Passeriformes in the less bulbous head, the much lesser development of the bicipital crest, the higher and more pronounced external tuber? osity, and the narrower, more ventrally projecting internal tuberosity. In the Piciformes the deltoid crest is much more expanded, the head more bulbous, the capital groove much deeper, and the internal tuberosity less perpendicular to the shaft than in Palaeotodus, although these differences are considerably less pronounced in the Galbulidae and Bucconidae. Within the Coraciiformes the humeri of the Upupidae, Phoeniculidae, and Meropidae have larger, more triangular deltoid crests than in Palaeotodus, while in the Coraciidae the bicipital crest is more extensive. The humerus in the Alcedinidae has the head more bulbous and situ? ated much higher above the external tuberosity, the shaft straighter, the internal tuberosity much heavier, and the bicipital surface much less pro? duced than in Palaeotodus. T h e humerus of Palaeotodus is most similar to that of the Todidae and the Momotidae. In the conformation of the internal tuberosity it is more similar to the Momo? tidae, whereas in the greater excavation of the ex? ternal tuberosity and ligamental furrow it more closely resembles the Todidae. The manner in which the skull was crushed in the type of Palaeotodus makes it appear smaller, while the distortion of the humerus is such as to make it appear wider and thus larger. Nevertheless, it is quite evident that the proportions of Palaeoto? dus are different from those of Todus, the wing being much larger in relation to the head. This difference in proportions may be due at least in part to the small size of Todus being sec? ondarily derived, since the species of this genus are the smallest members of the order Coraciiformes. In the evolution of vertebrates, body size usually changes at a more rapid rate than head size, so that small forms derived from larger ones tend to have proportionately larger heads, and vice versa. Many authors have remarked on the large-headed appear? ance of Todus in life. In the Oligocene, the Todi? dae were possibly more diverse than at present and probably included larger, more actively flying forms with better developed wings than the strictly sedentary modern todies. An Oligocene Motmot from Switzerland In 1839, von Meyer called attention to the re? mains of what he thought to be a passerine bird from slate deposits (Glarner Fischschiefer) in Switzerland, then considered to be of Cretaceous age. In a subsequent publication he named this specimen Prolornis glarniensis (von Meyer, 1844). NUMBER 27 115 Later (von Meyer, 1856), he emended the name to P. glaronensis and this spelling was in general use until Brodkorb (1971), whom I have followed, re? vived the original orthography. Lambrecht (1933) maintained Protornis as a genus incertae sedis in the Passeriformes. At that time the deposits from which the type of P. glarniensis was derived were regarded as upper Eocene in age. Subsequent studies have shown them to be of lower Oligocene age (Peyer, 1957). The type of P. glarniensis consists of a slab con? taining the bones of all four limbs, the pectoral girdle, a complete mandible, the quadrates, and a few vertebrae and ribs. These were insufficiently exposed when von Meyer studied them, but Peyer (1957) undertook further preparation of the type, illustrating his results with numerous photographs and x-radiographs. T h e fossil is slightly distorted from stresses imposed on the rock after deposition; Stiissi (1958) and Baumann (1958) have offered mathematical and optical corrections, respectively, for this distortion. Another less complete specimen was referred to Protornis, possibly glarniensis, by Peyer (1957). I have had access to casts of both these specimens, as well as to Peyer's excellent illus? trations. The casts were made by a copper electro? plate process and appear to be very accurate rep? resentations of the original specimens. After his study of the type of P. glarniensis, Peyer (1957) concluded that it belonged with the Alcedinidae (kingfishers) and more particularly that it was nearest to Dacelo. I agree with the as? signment of this form to the Coraciiformes, but numerous characters of its skeleton show conclu? sively that Protornis cannot be a kingfisher. Protornis glarniensis is a small bird, slightly smaller than the modern motmot Hylomanes momotula. As detailed by Peyer, many aspects of its structure demonstrate that it does not belong with the Passeriformes and the clearly anisodactyl feet eliminate the Piciformes from consideration. The mandibular symphysis is broad, flattened and somewhat spatulate, differing from most non- passerine landbirds except the Momotidae and Todidae. The overall conformation of the man? dible is in fact, markedly similar to that of the motmot genera Electron and Hylomanes and is quite distinct from that of the kingfishers, includ? ing the flat-billed genus Myioceyx (Figure 2). The symphysis is broader than in the Todidae and somewhat shorter than in the modern genera of Momotidae, being most similar in this respect to Hylomanes, which genus is generally conceded to be the most primitive of living motmots. In the mandibular articulation of Protornis the internal process is a long, thin splint set off from a well-developed retroarticular process by a distinct notch, with the actual articulating surface for the quadrate much reduced. This is exactly the condi? tion seen in the Momotidae and Todidae. In the Alcedinidae the articular cup for the quadrate is large and deep, the retroarticular process virtually absent, and the internal process wide, heavy, and triangular, quite unlike Protornis or the motmots and todies. Bee-eaters, Meropidae, have a fairly long, slender internal process, but it is not set off from the retroarticular by a notch, and the articu? lar cup is deep, as in kingfishers. Furthermore, the bill shape of Protornis is not at all like that of the Meropidae. The shape of the hypotarsus in Protornis is ex? actly as in motmots and differs from that of the kingfishers, in which it projects above the cotylae in a distinct point. The tarsometatarsus of Pro? tornis is only slightly shorter than the middle toe with claw, as in the motmots. In todies the tarsus is longer than the middle toe with claw, whereas in the kingfishers and bee-eaters the tarsus is squat and much shorter than the middle toe. T h e pro? coracoid process appears to be nearly absent in Protornis, as in motmots and todies, whereas it is better developed in kingfishers. From the evidence detailed above it is clear that Protornis does not belong with the Alcedinidae, where Peyer (1957) placed it. The proportions of the bill and of the hindlimb and toes preclude its assignment to the Todidae. In all of its important features it agrees with the Momotidae. It differs from the modern forms of the family mainly in the shorter mandibular symphysis and the higher, more expanded sternocoracoidal process of the coracoid. Protornis glarniensis should, therefore, be assigned to the family Momotidae. A second fossil from the Glarner Fischschiefer, consisting of a slab with both hindlimbs, the right wing, some ribs, and portions of the pelvis super? imposed on the sternum, was assigned to the genus Protornis by Peyer (1957), who suggested that it might, be referable to the species P glarniensis. This is plainly impossible, for the second specimen 116 SMITHSONIAN CONTRIBUTIONS TO PALEOBIOLOGY FIGURE 2.?Dorsal views of mandibles: a, Electron platyrhynchum; b, Protornis glarniensis (adapted from Peyer, 1957); c, Hylomanes momotula; d, Todus subulatus; e, Myioceyx lecontei; f, Dacelo novaeguineae. (Not to scale.) is much too large to belong to the same species as P. glarniensis; the carpometacarpus, for example, is twice as long. Furthermore, in the right foot of this specimen it can be clearly seen that both digits I and II are reversed (Figure 3)?a condition found only in the Trogonidae among modern birds. T h e rest of the skeleton of this specimen is gen? erally similar to that of modern trogons, although differing in some details. This specimen deserves a great deal more attention since it provides the NUMBER 27 117 FIGURE 3.?Diagram of right foot of the so-called second specimen of Protornis showing the heterodactyl condition typical of the Trogonidae. (Adapted from Peyer, 1957, and a cast of the specimen; the distal portion of the fourth toe is present as an impression in the matrix.) earliest evidence of the occurrence of the hetero? dactyl foot. It obviously cannot be assigned to Pro? tornis or the Momotidae and for the present should be regarded as belonging to the Trogonidae. Four fossil species of trogons are known?all from France (Brodkorb, 1971). Three of these, in the genus Archaeotrogon, are from the Phosphorites du Quercy, which range in age from upper Eocene to lower Oligocene, and are thus possibly contempor? aneous with the Swiss specimen. The fourth spe? cies, Paratrogon gallicus, is from lower Miocene (Aquitanian) deposits at Langy. A second species of Protornis, P. blumeri, was described from the Glarner Fischschiefer in 1865 by Heer (1876). T h e type appears to have been poorly preserved and has not been restudied, its whereabouts being unknown. Brodkorb (1971) placed this species, along with P. glarniensis, in the Alcedinidae, but considered its position uncertain. From the original illustration one cannot even as? certain that the specimen was avian. In view of this, and since more than one family of birds occurs in the Glarner deposits, P. blumeri should be rele? gated to the category of Aves incertae sedis. Discussion T h e ten families of the order Coraciiformes fall into several diverse groups whose relationships within and without the order are as yet uncertain. Sibley and Ahlquist (1972:230) maintained that, "no compelling evidence exists to ally any group of the Coraciiformes more closely to a non- coraciiform than to other members of the Coracii? formes." On the basis of biochemical analysis of egg-white proteins, Sibley and Ahlquist concluded, as have other taxonomists in the past, that within the Coraciiformes, the Alcedinidae, Todidae, Mo? motidae, and Meropidae appear to form a natural but distantly interrelated group. Feduccia (1975) discovered that these families possess a highly de? rived stapes, which is shared only with the Trogon? idae, and concluded that all five families are closely related. Contrary to most earlier opinions, Sibley and Ahlquist (1972:230) suggested that the Todi? dae are more closely allied to the Alcedinidae than to the Momotidae. The osteology of these families does not support this contention, and along with their distributional history strongly indicates that a fairly close affinity exists between todies and mot? mots and that these families differ considerably from the kingfishers. Seven of the ten families of Coraciiformes are confined to the Old World. Of approximately 89 Recent species of Alcedinidae, only six, in two genera, are found in the New World. Of these, two are in the genus Ceryle, which also contains two Old World species, while the genus Chloroceryle, which is only weakly differentiated from Ceryle, contains four species endemic to the New World. Clearly the kingfishers are an Old World family that has only recently invaded the Americas. Thus , the Todidae and Momotidae are the only truly New World families of modern Coraciiformes. Recent motmots are neotropical in distribution, ranging from southern Mexico south through Bra? zil. In a classical exercise in zoogeography, Chap? man (1923) analyzed the distribution of the genera, species, and subspecies of motmots, concluding that they had originated in Central America, the few South American forms having been derived from the north. Lonnberg (1927), noting that Central and North America probably presented a more or less continuous tropical environment in the Ter? tiary, felt that the motmots could as easily be con- 118 SMITHSONIAN CONTRIBUTIONS TO PALEOBIOLOGY sidered North American in origin. A North or Central American origin of the modern members of the family, as opposed to a South American one, has properly gained general acceptance. Neverthe? less, this leaves unanswered the question of the origins of ancestral motmots. The modern todies, confined to the West Indies, are also thought of as being North American in origin. This is due in part to their presumed re? lationship with the motmots and in part to the North American derivation of most of the rest of the Antillean avifauna (Bond, 1966). It might then be asked whether the todies evolved their distinc? tive characteristics from some momotid-like ances? tor after arriving in the Greater Antilles, or had already assumed these characteristics before colon? izing the islands. Because of the small size and feeble flight of modern todies, Bond (1966) expressed reservations about their ability to cross even narrow water gaps and suggested that they might have been rafted to the West Indies from Central America. However, because the five species of modern todies are very similar in plumage and morphology, one must as? sume that members of the genus Todus have been able to cross the water barriers between the Greater Antilles within relatively recent geologic time. Moreover, since there are two species of Todus on Hispaniola, one must either assume sympatric speciation or a double invasion of the island. Bond's own remarks (1974) on the greater similar? ity of the voice of Hispaniolan T. angustirostris to that of Cuban T multicolor than to that of the other Hispaniolan species, T. subulatus, suggest a double invasion. Thus, if todies were able to cross the water barriers between the islands of the Greater Antilles they might as easily have crossed from the mainland. Furthermore, the evidence pro? vided by Palaeotodus shows that in the Oligocene, todies were larger and had proportions suggestive of greater powers of flight. It therefore seems pos? sible that todies might have colonized the West Indies over water as easily as, say, kingfishers, and it is not necessary to invoke rafting to explain their present distribution. Without doubt, the order Coraciiformes, as tra? ditionally conceived, arose in the Old World. The existence of Protornis in the lower Oligocene of Switzerland now provides evidence that the family Momotidae, presently confined to the New World, actually had its origins in the Old World. The place and time of origin of the Todidae are un? certain. The Orellan land-mammal stage repre? sents a geologically very short span of time follow? ing the much longer Chadronian stage and pre- ceeding the Whitneyan stage, the latter also representing a very short span of time. The de? posits from which Palaeotodus was recovered are about 30 million years old and have traditionally beeji regarded as middle Oligocene, although there is as yet no paleontological correlation between the North American terrestrial deposits of so-called Oligocene age and those of Europe. By the reduced ossification of the skull, Palaeotodus certainly seems to be referable to the Todidae rather than the Momotidae, but perhaps with material from earlier in the Oligocene it would not be possible to distinguish the two families, the family Todidae having assumed its characteristics since that time. Probably through a combination of climatic change and competition with more advanced land birds, the motmot-tody group was entirely sup? planted in the Old World. T h e deterioration of tropical conditions in North America in the late Tertiary left motmots only in Central America, from whence they have spread into South America since the closing of the Panamanian seaway in the late Pliocene. Similar factors affected the North American todies and only the isolated West Indian relicts of the genus Todus have survived up to the present. Feduccia and Martin (p. 110, herein) have shown that the predominant order of small land birds of the Eocene in North America was the Piciformes. It is now becoming evident that the Oligocene was similarly important in the evolution of the Coracii? formes. Although the evidence is far from con? clusive, if the Coraciiformes (including the Tro? gonidae) were not the predominant perching land birds of the Oligocene, they were certainly much more prevalent than today. Recently I have ex? amined a number of fragments of small land birds of Chadronian and Orellan age from the western United States. All of these appear to be referable either to the Coraciiformes or Piciformes and defi? nitely are not passerine. Thus, it would appear that the Passeriformes may not have gained a strong foothold in North America until the Miocene. NUMBER 27 119 Literature Cited Baumann, E. 1958. Affine Entzerrug mit einfachen optischen Mitteln. Schweizerische Palaeontologische Abhandlungen, 73:17-21, 4 figures. [Separate.] Bock, W. J. 1962. The Pneumatic Fossa of the Humerus in the Passeres. Auk, 79(3):425-443, 2 figures. Bond, J. 1966. Affinities of the Antillean Avifauna. Caribbean Journal of Science, 6:173-176. 1974. Nineteenth Supplement to the Check-list of Birds of the West Indies (1956). 12 pages. Philadelphia: Academy of Natural Sciences of Philadelphia. Brodkorb, P. 1971. Catalogue of Fossil Birds, Part 4 (Columbiformes through Piciformes). Bulletin of the Florida State Museum, Biological Sciences, 15(4): 163-266. Chapman, F. M. 1923. The Distribution of the Motmots of the Genus Momota. Bulletin of the American Museum of Natural History, 48:27-59, 4 figures. Feduccia, A. 1975. Morphology of the Bony Stapes (Columella) in the Passeriformes and Related Groups: Evolutionary Implications. The University of Kansas Museum of Natural History Miscellaneous Publication, 3:1-34, 7 figures, 16 plates. Heer, O. 1876. The Primaeval World of Switzerland. Volume 1. London: Longmans, Green and Co. [English trans? lation of Die Urwelt der Schweiz, Volume 1. Zurich, 1856 (not seen).] Lambrecht, K. 1933. Handbuch der Palaeomithologie. xix + 1024 pages. Berlin: Gebriider Borntrager. Lonnberg, E. 1927. Some Speculations on the Origin of the North American Ornithic Fauna. Kungliga Svenska Ven- tenshapakademiens Handlingar, series 3, 4 (6): 1-24. von Meyer, H. 1839. Ein Vogel im Kreideschiefer des Kantons Glaris. Neues Jahrbuch fiir Mineralogie, Geognosie, Geol? ogie und Petrefaktenkunde, 1:683-685. 1844. [Letter.] Neues Jahrbuch fiir Mineralogie, Geog? nosie, Geologie und Petrefaktenkunde, 6:329-340. 1856. Schildkrote und Vogel aus dem Fischschiefer von Glarus. Palaeontographica, 4(3):83-95, 2 plates. Newton, A. 1896. A Dictionary of Birds. 1088 pages. London: Adam and Charles Black. Peyer, B. 1957. Protornis glaronensis H. v. Meyer Neubeschreibung des Typusexemplares und eines weiteren Fundes. Schweizerischen Palaontologischen Abhandlungen, 73:1-47, 26 figures, 11 plates. Raczyriski, J., and A. L. Ruprecht 1974. The Effect of Digestion on the Osteological Com? position of Owl Pellets. Acta Ornithologica, 14(2): 1-36. Sibley, C. G., and J. E. Ahlquist 1972. A Comparative Study of the Egg White Proteins of Non-Passerine Birds. Peabody Museum of Nat? ural History Yale University Bulletin, 39:1-276, 37 figures. Stiissi, F. 1958. Die Entzerrung von Fossilien am Beispiel des Protornis glaronensis. Schweizerischen Palaontolo? gischen Abhandlungen, 73:1-16, 13 figures. [Sepa? rate.] Two New Species of Aegialornis from France, with Comments on the Ordinal Affinities of the Aegialornithidae Charles T. Collins ABSTRACT Collections from the upper Eocene-lower Oligo? cene phosphorite deposits of Quercy, France, in? clude numerous fossil elements attributed to two species of Aegialornis. An examination of the hu? meri in this series disclosed the presence of two unrecgonized species, which are newly described here as Aegialornis wetmorei and A. broweri. Pre? liminary study of the other skeletal elements pre? viously assigned to Aegialornis indicates that at least some of them are probably referable to the Charadriiformes and the Coraciiformes. T h e hu? meri of Aegialornis show closer similarity to Chor- deiles than to any members of the Hemiprocnidae or Apodidae, and, therefore, the Aegialornithidae is removed from the Apodiformes and placed in the Caprimulgiformes near the Caprimulgidae. Introduction In the Museum National D'Histoire Naturelle, Paris, and the British Museum (Natural History), are extensive collections of bird fossils from the upper Eocene to lower Oligocene phosphorite de? posits of Quercy, France. These include numerous distinctive humeri and some additional material referred to two species in the genus Aegialornis: A. gallicus Lydekker and A. leenhardti Gaillard. An additional form, Primapus lacki, was later de? scribed from the lower Eocene London Clay of Britain (Harrison and Walker, 1975). Further study of the Quercy material indicates the presence of two additional species of Aegialornis. This ge- Charles T. Collins, Department of Biology, California State University, Long Beach, California 90840. nus has been placed in a distinct family, the Aegialornithidae, the taxonomic history of which has been summarized by Harrison (1975). T h e family was first proposed by Lydekker (1891) who treated it as incertae sedis near the Laridae. T h e subsequent view of Milne-Edwards (1892) and Gaillard (1908) that Aegialornis is more properly included in the Apodiformes has been widely, though seemingly uncritically, accepted. Brodkorb (1971), on the basis of the evidence now presented here, included the Aegialornithidae in the Capri? mulgiformes, a placement recently disputed by Harrison (1975). It is the purpose of this paper to review the species of Aegialornis and to comment on the possible affinities of the Aegialornithidae. A wide array of fossil and recent material was ex? amined in this study. Included were the types of Aegialornis gallicus, A. leenhardti, and Tachyornis hirundo, and much of the additional material re? ferred to these species. Recent skeletons examined included many genera of Caprimulgiformes, partic? ularly Chordeiles, Caprimulgus, and Phalaenopti- lus, and from one to several species of swifts and crested swifts in the genera Hemiprocne, Cypse- loides, Streptoprocne, Apus, Aeronautes, Reinarda, Hirundapus, and Chaetura. ACKNOWLEDGMENTS.?The study of these fossils, part of a wider study of the biology and evolution of swifts, has been generously supported by research grants and a postdoctoral fellowship from the Frank M. Chapman Memorial Fund of the Ameri? can Museum of Natural History. Fossil material was obtained on loan from the Institut de Paleon? tologie, Museum National D'Histoire Naturelle, Paris (PM); the Department of Paleontology, British Museum (Natural History) (BMNH); and the Musee D'Histoire Naturelle de Montauban. 121 122 SMITHSONIAN CONTRIBUTIONS TO PALEOBIOLOGY Recent comparative material of Hemiprocne was obtained from the National Museum of Natural History, Smithsonian Institution. I am indebted to the curators of these institutions for their kind? nesses. C. J. O. Harrison and C. A. Walker gener? ously provided advance copies of their papers and photographs of Primapus. John Auth provided essential photographic assistance. AEGIALORNITHIDAE Lydekker, 1891 Aegialornis Lydekker, 1891 SYNONYMS.?Tachyornis Milne-Edwards, Belornis Milne-Edwards, 1893. 1892; Aegialornis gallicus Lydekker, 1891 FIGURES 1, 4b TYPE-LOCALITY.?Departement de Lot, Bach near Lalbenque, France. SYNONYM.?Tachyornis hirundo Milne-Edwards, 1892. France, Phosphate de Chaux ( = Phosphor? ites du Quercy, fide Gaillard, 1908). This species is represented by at least 20 hu? meri: the type-series of 13 and 2 additional speci? mens in the British Museum, and 5 specimens, in? cluding the type of Tachyornis hirundo, in the Paris Museum. Referred material includes 2 cora- coids, 3 ulnae, 11 carpometacarpi, and 3 proximal phalanges of digit II (BMNH); and 26 tarsometa? tarsi (PM). As noted by Lydekker (1891) and Harrison and Walker (1975), the humerus is short and stout with a long, prominent, angular deltoid crest; deep ligamental furrow; large, flattened ectepicondylar process; laterally compressed head; broad bicipital surface and bicipital crest; and deep brachial depression. T h e humeri of A. gallicus are jfl| FIGURE 1.?Left humerus of Aegialornis gallicus: a, anconal view; b, palmar view; c, external view. (X 4.) NUMBER 27 123 TABLE 1.?Ranges and means (in parentheses) of measurements (mm) of humeri in Aegialornis Character Overall length Shaft width Shaft depth Width of distal end Depth of distal end Height of ectepicondylar process Height of ectepicondylar process as % of total length A. leenhardti n = 2 A. gallicus n = 2 0 A. wetmorei A. broweri n = 1 29.2-29.8 (29.5) 3.7-3.7 (3.7) 2.7-2.8 (2.8) 7.0-7.3 (7.2) 3.9-4.1 (4.0) 5.9-6.1 (6.0) 20.33 24.3-27.4 (25.9) 2.5-3.3 (3.1) 2.2-2.5 (2.4) 5.6-6.3 (5.9) 3.6-4.0 (3.7) 5.5-6.3 (6.0) 23.04 21.8-22.4 (22.0) 2.6-2.8 (2.7) 2.0-2.1 (2.1) 4.9-5.0 (5.0) 3.2-3.4 (3.3) 6.1-6.2 (6.2) 28.03 19.1 2.3 1.7 4.2 2.7 4.8 25.1 smaller than those of A. leenhardti (Table 1), but larger than those of other species of Aegialornis or Primapus. The referred elements, not all of which appear to be properly assigned to Aegialornis, are discussed below. Aegialornis leenhardti Gaillard, 1908 FIGURES 2, 4a SYNONYM.?Originally proposed as Aegialornis leehnardti Gaillard, 1908; spelling emended to leenhardti by Brodkorb, 1971:233. TYPE-LOCALITY.?Phosphorites du Quercy, France. The holotype right humerus (Musee D'Histoire Naturelle de Montauban) and a previously un? recognized left humerus (PM) agree in being larger than A. gallicus and in having a larger and more distally located ectepicondylar process (Table 1). Additional material of this species (not ex? amined in this study) is present in other museum collections (Gaillard, 1908; P. Ballmann, pers. comm.). A left tarsometatarsus from Caylux (Mu? seum de Lyon) figured by Gaillard (1908) appears similar to the numerous tarsometatarsi he referred to A. gallicus and which were examined in this study. These specimens are, in my opinion, from an undescribed species possibly belonging in the Coraciiformes. FIGURE 2,.?Holotype right humerus of Aegialornis leenhardti, palmar view. (X 4.) 124 SMITHSONIAN CONTRIBUTIONS TO PALEOBIOLOGY Aegialornis wetmorei, new species FIGURES 3a, 4c HOLOTYPE.?Complete right humerus (PM 15478) from the upper Eocene-lower Oligocene Phos? phorites du Quercy, France. MEASUREMENTS OF HOLOTYPE.?Overall length from head to internal condyle 21.8 mm, width and thickness of shaft at midpoint 2.8 X 2.1 mm, great? est width of distal end 5.0 mm, thickness through internal condyle 3.4 mm, height of proximal edge of ectepicondylar process above distal edge of ectepicondyle 6.3 mm. PARATYPES.?Two nearly complete left humeri (PM 15479 and 15480) slightly abraded on deltoid crest, bicipital crest, and internal tuberosity; from the same deposits as the type. ETYMOLOGY.?This species is named after Dr. Alexander Wetmore on the occasion of his nine? tieth birthday, in recognition of his many contri? butions to the field of paleornithology. DIAGNOSIS AND DESCRIPTION.?These humeri are appreciably smaller and more slender than the smallest humerus of A. gallicus (the type of Tachy? ornis hirundo) or that of the still larger species A. leenhardti. T h e ectepicondylar process is less ro? bust than in A. leenhardti or A. gallicus and is lo? cated farther proximally, being well above the proximal edge of the brachial depression, whereas the ectepicondylar process is located at the level of the proximal end of the brachial depression in A. gallicus and A. broweri and is somewhat more distal in A. leenhardti (Table 1). Aegialornis broweri, new species FIGURES 3b, 4d HOLOTYPE.?Nearly complete right humerus (PM 15481) from the upper Eocene-lower Oligocene Phosphorites du Quercy, France. MEASUREMENTS OF HOLOTYPE.?Overall length from head to internal condyle 19.1 mm, width and thickness of shaft at midpoint 2.3 X 1.7 mm, great? est width of distal end 4.3 mm, thickness of distal end through external condyle 2.6 mm, thickness through internal condyle 2.7 mm, height of proxi? mal edge of ectepicondylar process above distal edge of ectepicondyle 4.8 mm. ETYMOLOGY.?This species is named after Dr. Lincoln P. Brower in recognition of his contribu? tions to other fields of biology and also for instill? ing in me a way of thinking I have tried to follow throughout my career. DIAGNOSIS AND DESCRIPTION.?The single known humerus of A. broweri differs from A. leenhardti, A. gallicus, and A. wetmorei in being smaller, with a proportionately more slender shaft. T h e ectepi? condylar process is more proximally located than in either A. leenhardti or A. gallicus, but is not as far proximal as in A. wetmorei. The brachial de? pression is less excavated and the muscle attach? ments of the proximal end are less well defined than in the other species of the genus. The type shows no signs of immaturity and must therefore pertain to an additional small species of Aegialor? nis in this fauna. T h e lower Eocene species Prima- pus lacki is still smaller, the humerus being little more than two-thirds the length of that of A. broweri. FIGURE 3.?Holotype right humeri of Aegialornis, anconal views: a, A. wetmorei, new species; b, A. broweri, new species. (X 4.) Discussion It is perhaps surprising that there should be four NUMBER 27 125 such closely related species of Aegialornis (Figure 4) in the same fauna. The differences in the posi? tion of the ectepicondylar process in these forms, however, make it unlikely that the apparent spe? cies limits are simply breaks in a continuum of one or two highly variable or sexually dimorphic spe? cies. Primapus lacki from the lower Eocene of Brit? ain differs from the four species of Aegialornis in being much smaller and in having a slightly bi? lobed appearance to the bicipital crest and the entepicondyle projecting distally beyond the in? ternal condyle (Harrison and Walker, 1975). The putative swift, Cypselavus gallicus Gaillard, from the upper Eocene-lower Oligocene Phosphorites du Quercy, was not examined in this study, but as noted elsewhere (p. 131, herein), it appears from the published illustrations that it may be a small member of the Aegialornithidae, about the same size as Primapus lacki. The earliest known modern swift (Apodidae) is Cypseloides ignotus (Milne- Edwards) from the lower Miocene (Aquitanian) of France. The affinity of the Aegialornithidae to the Apod? idae and Hemiprocnidae of the suborder Apodi, has been accepted, largely uncritically, since the early suggestions of Milne-Edwards (1892) and Gaillard (1908). This action has recently been en? dorsed by Harrison (1975) on the basis of a review of the humeri and other referred elements of Aegialornis gallicus and Primapus lacki. From my study of the referred material of A. gallicus I am convinced that the coracoids, the proximal pha? langes of digit 2, and the tarsometatarsi belong to species in the orders Charadriiformes and Coracii? formes, and thus cannot be used to elucidate the ordinal affinities of Aegialornis. The similarity of some of these elements to those of the Laridae was noted by Lydekker (1891) in the original descrip? tion of Aegialornis. Until it is possible to restudy all of the referred material, it seems wisest to con? fine discussion of the possible affinities of Aegialor? nis to characters of the humerus, the type-element in all the species of the Aegialornithidae. The original allocation of Aegialornis to a fam- FIGURE 4.?Size comparison of palmar views of right humeri of the four species of Aegialornis: a, A. leenhardti, holotype; b, A. gallicus;,c, A. wetmorei, new species, holo? type; d, A. broweri, new species, holotype. (X 3.) 126 SMITHSONIAN CONTRIBUTIONS TO PALEOBIOLOGY ily within the Apodi seems to have been based principally on the superficial resemblance of the short and stout humeri to those of the Hemiproc- nidae and Apodidae. Harrison (1975) also cites the prominent ectepicondylar process, shorter and more abruptly projecting deltoid crest, less prox? imally deflected internal tuberosity, and the pres? ence of the distinct flange on the bicipital crest as characteristics shared with the Apodi. Although there are some definite similarities between the hu? meri of Aegialornis and those of the Apodi, par? ticularly Hemiprocne, I feel there is a greater re? semblance between Aegialornis and some members of the Caprimulgidae, particularly Chordeiles and related genera (the Chordeilidae of Oberholser, 1914). In Aegialornis the head is deflected anconally and the distal end is directed palmarly. This con? dition, somewhat accentuated by the longer shaft, is also found in Chordeiles. The humerus is notably straight in Hemiprocne and the primative swifts of the subfamily Cypseloidinae; only a slight anconal deflection of the head is present in the Apodinae and Chaeturinae. The deep ligamental furrow in Aegialornis and Chordeiles extends well out onto the internal tuberosity, where it curves to ap? proach the distal margin. In the Apodi the liga? mental furrow is shorter and straighter, ending near the proximal base of the internal tuberosity. In Chordeiles the internal tuberosity is deflected slightly more proximally at the tip than in Aegia? lornis, and the pnenumatic fossa is more exposed. In the Apodi the internal tuberosity projects laterally or is deflected distally and bears little resemblance to that of Aegialornis. A distinct similarity exists be? tween Aegialornis and Chordeiles in the thickened median crest and broadly excavated capital groove proximal to it. A slight projecting flange on the bi? cipital crest of Aegialornis can also be noted in some specimens of Chordeiles. Although this flange is usually much more highly developed in Aegialor? nis, considerable variation is shown in the speci? mens examined in this study, with some individuals showing only slight development of this feature. The shape of the deltoid crest is very similar in Chordeiles and Aegialornis and lacks the more abrupt taper and concave proximal edge of the Apodi. The deltoid crest is appreciably different in other genera of the Caprimulgidae (e.g., Capri- mulgus and Phalaenoptilus), which have a more flattened lateral edge and a longer, more gradual slope to the distal edge. Thus , only some of the genera of Caprimulgidae have the "longer and more smoothly rounded" profile of the deltoid crest incorrectly attributed to the entire family by Har? rison (1975). The distal end of the humerus shows many simi? larities between Aegialornis, Hemiprocne, and to a lesser extent Streptoprocne, in the flared external tricipital groove and medially expanded entepi? condyle. Aegialornis and Chordeiles are alike in having a broader and more protruding attachment for the anterior articular ligament and a deeper intercondylar groove. A large peglike ectepicon? dylar process, the single most distinctive character? istic of the humeri of swifts and Aegialornis, is accompanied by a distinct, raised lateral muscle scar at its base in Aegialornis which is lacking in the Apodi. A small ectepicondylar process and as? sociated muscle scar is also present in Chordeiles and, as noted by Harrison (1975), in Podager. In the Apodi the ectepicondylar process is never as thickened as in Aegialornis and is always substan? tially more proximally located. In some of the Apodi there is also a secondary process located dis? tal to the ectepicondylar process. This is particu? larly well developed in the Hemiprocnidae and Cypseloidinae but completely absent in Aegialor? nis. Within the Caprimulgidae there is consider? able difference in the appearance of the distal portion of the humerus, as well as in the develop? ment of the ectepicondylar process. A strong re? semblance to Aegialornis can be found in Chor? deiles and related genera, but not in Caprimulgus, Phalaenoptilus, and Eurostopodus. Although the Aegialornithidae show some simi? larities to the Hemiprocnidae, I feel that the ma? jority of the characters of the humeri indicate a closer relationship with the Chordeiles group of the Caprimulgidae. I therefore place the Aegial? ornithidae as a family within the Caprimulgi? formes, possibly allied to the Caprimulgidae. With the tentative removal of Cypselavus galli? cus from the Apodidae to the Aegialornithidae, the earliest fossil swifts appear in the lower and middle Miocene deposits of France (p. 131, herein). There is thus no longer any evidence to support the earlier notion that the Apodidae and Aegial? ornithidae were contemporaneous during the late Eocene or early Oligocene. Therefore, the possi- NUMBER 27 127 bility exists that the Aegialornithidae are repre? sentatives of a caprimulgiform lineage that later gave rise to the swifts and crested swifts. Although a close relationship between the Caprimulgiformes and the Apodi is not supported by presently avail? able biochemical information (Sibley and Ahl? quist, 1972), neither does this information pro? vide any conclusive evidence of the affinities of swifts to other groups. A caprimulgiform- apodiform relationship should be reviewed further when additional fossil elements are found that can definitely be assigned to the Aegialornithidae. Literature Cited Brodkorb, P. 1971. Catalogue of Fossil Birds, Part 4 (Columbiformes through Piciformes). Bulletin of the Florida State Museum, Biological Sciences, 15(4): 163-266. Gaillard, C. 1908. Les oiseaux des phosphorites du Quercy. Annales de I'Universite de Lyon, new series, 1(23): 1-178, 37 figures, 8 plates. Harrison, C. J. O. 1975. Ordinal Affiinities of the Aegialornithidae. Ibis, 117(2):164-170, 5 figures. Harrison, C. J. O., and C. A. Walker 1975. A New Swift from the Lower Eocene of Britain. Ibis, 117(2): 162-164, plates 14-15. Lydekker, R. 1891. Catalogue of the Fossil Birds in the British Mu? seum (Natural History). 368 pages. London: Taylor and Francis. Milne-Edwards, A. 1892. Sur les oiseaux des depots Eocenes des phosphates de chaux du sud de la France. Pages 60-80 in volume 2 of C. R. 2me International Ornithological Congress, Budapest 1891. 1893. [Letter.] Bulletin of the British Ornithologists' Club, 1:53-54. Oberholser, H. C. 1914. A Monograph of the Genus Chordeiles Swainson, Type of a New Family of Goatsuckers. Bulletin of the United States National Museum, 86(1): 1-123, 6 plates. Sibley, C. G., and J. E. Ahlquist 1972. A Comparative Study of the Egg White Proteins of Non-passerine Birds. Peabody Museum of Nat? ural History, Yale University, Bulletin, 39:1-276, 37 figures. A Review of the Lower Miocene Swifts (Aves: Apodidae) Charles T. Collins ABSTRACT Three nominal species of swifts have been de? scribed from lower Miocene (Aquitanian) depos? its of France. Re-examination of these forms, Cypselus [ = Apus'] ignotus Milne-Edwards, Collo- calia incerta Milne-Edwards, and Cypselavus inter? medins Gaillard, indicates that they are attrib? utable to a single species, ignotus, referable to the modern genus Cypseloides. This provides the first occurrence of the Cypseloidinae in the fossil record and indicates a possible origin in the Old World for this primitive group of swifts, presently re? stricted to the New World. Introduction Up to now, five species of fossil swifts have been described, all coming from Tertiary deposits in France. The present paper is aimed at reviewing the three nominal species from deposits of early Miocene age, with comparisons being made with a much wider array of skeletal material of modern swifts than were available to the original describers of the fossil forms. Recent swifts examined in this study included Cypseloides rutilus, C. cherriei, C. niger, and Streptoprocne zonaris in the Cypse? loidinae; from one to several species in the genera Apus, Aeronautes, Cypsiurus, Tachornis, Reinarda, and Panyptila in the Apodinae; and Chaetura, Col- localia, and Hirundapus in the Chaeturinae. ACKNOWLEDGMENTS.?I thank the Frank M. Chap? man Memorial Fund of the American Museum of Charles T. Collins, Department of Biology, California State University, Long Beach, California 90840. Natural History for support and I am also indebted to Dr. J. P. Lehman of the Institut de Paleontol? ogie, Museum National D'Histoire Naturelle, Paris, for lending the types of Cypselus ignotus and Collocalia incerta. Family APODIDAE Subfamily CYPSELOIDINAE Cypseloides ignotus (Milne-Edwards, 1871) Cypselus ignotus Milne-Edwards, 1871:394, pl. 177: figs. 9-13. Apus ignotus.?Paris, 1912:286. Collocalia incerta Milne-Edwards, 1871:394, pl. 177: figs. 1-8. Cypselavus intermedius Gaillard, 1939:42, fig. 20. From the Aquitanian deposits at St.-Gerand-le- Puy, Departement de Allier, France, Milne- Edwards (1871) described a new species of swift, Cypselus [=Apus~\ ignotus. This was based on a complete right carpometacarpus and a left ulna with the proximal end badly chipped. When I ex? amined these specimens, a second left ulna, excel? lently preserved, had somehow been associated with the two syntypes. This is identical to the first ulna and I therefore refer it to the species ignotus also. From the same deposits, Milne-Edwards (1871) named a second species of swift, Collocalia incerta, based on a single well-preserved left tibio? tarsus. This was characterized as being much too small to have come from the same species as the wing elements assigned to Apus ignotus. Consider? ably later, Gaillard (1939) reported a left humerus of a swift from Aquitanian deposits at Chavroches, also i n ' t he Departement de Allier, which he de? scribed as a new species, iritermedius, in the 129 130 SMITHSONIAN CONTRIBUTIONS TO PALEOBIOLOGY Eocene-Oligocene genus Cypselavus (Gaillard, 1908). I have studied the original material of Apus ignotus and Collocalia incerta as well as Gaillard's (1939) description and illustrations of Cypselavus intermedins. While all these fossils clearly belong to the Apodidae, it is equally apparent that none is referable either to Apus or to Collocalia. In size and conformation, the two ulnae of ignotus (Figure la) are very similar to those of some of the smaller species of the genus Cypse? loides. They lack the well-developed olecranal process found in the subfamilies Apodinae and Chaeturinae. This condition is typical of the Cypseloidinae. The fossil ulnae are slightly longer and stockier than the ulnae of Cypseloides rutilus or C. cherriei, and the prominence for the anterior articular ligament is more shelf-like. Also, the ex- ^~~\ FIGURE 1.?Bones of Cypseloides ignotus (Milne-Edwards): a, referred left ulna; b, syntype right carpometacarpus; c, left tibiotarsus (holotype of Collocalia incerta), anterior view; d, same, posterior view. (Approximately X 3.5, c and d at slightly different magnifications.) ternal cotyla appears slightly more undercut at its palmar edge and the distal ligamental attachment of the carpal tuberosity is less laterally flared. The carpometacarpus of swifts shows less marked distinctions between the subfamilies than does the ulna. That of ignotus (Figure lb) is somewhat longer and stockier than in Cypseloides rutilus or C. cherriei, but it does have the more widely flared pollical facet of metacarpal I and the more pro? nounced tendinal groove on metacarpal II typical of the Cypseloidinae. The fossil also has a broader and more flared tuberosity of metacarpal II, pro? viding a wider articular facet for digit II, which is typical of the two smaller species of Cypseloides studied, but not of swifts of other subfamilies. As noted by Milne-Edwards (1871) the tibio? tarsus of Collocalia incerta (Figure \c,d) is indeed more delicate than would be expected for any member of the Apodinae or Chaeturinae of the size of Apus ignotus. However, the tibiotarsus in the Cypseloidinae is proportionately more slender than in the other subfamilies of swifts, particularly the Apodinae. There is, in fact, a very close agree? ment in overall size and morphology between the type of Collocalia incerta and Recent specimens of Cypseloides rutilus. The posterior intercondylar groove of incerta is not deeply excavated as it is in members of the Apodinae and Chaeturinae, in? cluding Apus and Collocalia. The proximal por? tion of the shaft is straight, as in Cypseloides, and not distinctly bent laterally as typical of many other swifts. The fossil element is slightly smaller and stockier than in C. rutilus (C. cherriei has a much longer tibiotarsus than C. rutilus in spite of its having wing elements similar in size to both C. rutilus and A. ignotus), and the internal liga? mental prominence is less developed but more ex? cavated under the lip of the rotular crest. The wing elements of ignotus are clearly those of a small swift belonging to the genus Cypseloides. The tibiotarsus of incerta similarly shows affinities to Cypseloides particularly to C. rutilus. Con? trary to Milne-Edwards (1871), it is entirely probable that these fossils, which are from the same locality and horizon, come from the same species. This species should now be known as Cypseloides ignotus (Milne-Edwards) with incerta becoming a junior synonym, ignotus being chosen on the basis of line priority. In the referred ulna of Cypseloides ignotus, the NUMBER 27 131 maximum length is 17.9 mm, distal width 3.2 mm, proximal width 3.7 mm, and shaft width 1.6 mm. No accurate length could be determined for the chipped ulna in which the distal width is 3.2 mm, proximal width 3.7 mm, and shaft width 1.8 mm. The single carpometacarpus measures 16.4 mm in total length, proximal height 5.2 mm, proximal width 2.35 mm, and distal width 3.95 mm. T h e tibiotarsus has a total length of 21.1 mm, width across condyles 2.2 mm, width across proximal ar? ticular surfaces 2.5 mm, and shaft dimensions of 0.9 X 1.0 mm at the narrowest point and 1.0 X 1.5 mm at the middle of the fibular crest. The type-humerus of Cypselavus intermedius Gaillard (1939) was not examined in this study, but from the original figures it appears to have the distinctively longer and narrow proportions char? acteristic of the species of Cypseloides. As was noted by Lowe (1939:324), the ectepicondylar process of intermedius is much more distally po? sitioned than in any of the modern forms of the Apodinae or Chaeturinae but is only slightly more distal than in Cypseloides, a genus that was not compared by earlier workers. The measurements of the type of C. intermedius as given by Gaillard (1939:43) are: total length 11 mm, proximal width 4.5 mm, distal width 3 mm. Thus, this specimen agrees closely in size with specimens of modern Cypseloides rutilus and C. cherriei, and it would therefore also be of the same approximate size as C. ignotus. The type of Cypselavus intermedius comes from the same horizon and from a locality close to that of Cypseloides ignotus. Since it also appears to belong to the genus Cypseloides and is of the same size as C. ignotus, I feel that Cypsela? vus intermedius should also be synonymized with Cypseloides ignotus. As a result, the genus Cypsela? vus Gaillard is reduced to a single species, C. galli? cus, from the upper Eocene or lower Oligocene (Phosphorites du Quercy) of France; the genus Collocalia is deleted from the fossil record; and the earliest fossil possibly attributable to Apus now be? comes Apus gaillardi (Ennouchi) from the upper middle Miocene (Tortonian) of France (Brod? korb, 1971). Although the specimens of Cypselavus gallicus and Apus gaillardi were not examined in this study, the published illustrations are sufficient to determine that neither species shows any similari? ties to Cypseloides ignotus or the modern Cypselo? idinae. In fact, Cypselavus gallicus shows a dis? tinctly closer resemblance to the Aegialornithidae, the humerus agreeing in size with the newly described small aegialornithid Primapus lacki, from the lower Eocene of Britain (Harrison and Walker, 1975). In the published illustrations (Gail? lard, 1908), the humerus of Cypselavus gallicus appears to lack the prominant ectepicondylar process seen in the Aegialornithidae, but this could well be the result of damage. T h e illustra? tions of the humerus of Apus gaillardi (Ennouchi, 1930) show it to have the general proportions of the modern Apodidae and Chaeturinae. This spe? cies, and an additional swift from the upper Mio? cene of Italy, are currently under review elsewhere (P. Ballmann, pers. comm.). T h e Cypseloidinae (see Brooke, 1970:14-15 for use of this term) appears to be the most primitive subfamily of the Apodidae. It is therefore not un? expected that an extinct species of Cypseloides be among the earliest known swifts. Like the vultures of the family Cathartidae [ = Vulturidae] , the modern species of Cypseloidinae are confined to the New World; but also like the Cathartidae (Cracraft and Rich, 1972), they can now be shown to have had a past distribution and possible origin in the Old World. Further elucidation of the origin and evolution of the Apodidae will have to await a review of additional modern forms and the remain? ing fossil swifts, as well as the swift-like members of the Aegialornithidae (see Harrison and Walker, 1975; Harrison, 1975, Collins, pp. 121-127, herein). Literature Cited Brodkorb, P. 1971. Catalogue of Fossil Birds, Part 4 (Columbiformes through Piciformes). Bulletin of the Florida State Museum, Biological Sciences, 15(4): 163-266. Brooke, R. K. 1970. Taxonomic and Evolutionary Notes on the Sub? families, Tribes, Genera and Subgenera of the Swifts (Aves: Apodidae). Durban Museum Novitates, 9(2): 13-24. Cracraft, J., and P. V. Rich 1972. The Systematics and Evolution of the Cathartidae in the Old World Tertiary. Condor, 74(3):272-283, 10 figures. 132 SMITHSONIAN CONTRIBUTIONS TO PALEOBIOLOGY Ennouchi, E. 1930. Contribution a I'etude de la faune du Tortonien de La Grive-St-Alban (Isere). 135 pages, 6 plates. Paris: Les Presses Modernes. Gaillard, C. 1908. Les oiseaux des phosphorites du Quercy. Annales du Universite de Lyon, new series, 1(23): 1-178, 37 figures, 8 plates. 1939. Contributions a I'etude des oiseaux fossiles. Ar? chives du Museum d'Histoire Naturelle de Lyon, 15(m?moire 2): 1-100, 34 figures. Harrison, C. J. O. 1975. Ordinal Affinites of the Aegialornithidae. Ibis, 117(2): 164-170, 5 figures. Harrison, C. J. O., and C. A. Walker 1975. A New Swift from the Lower Eocene of Britain. Ibis, 117(2): 162-164, 2 plates. Lowe, P. R. 1938. On the Systematic Position of the Swifts (Suborder Cypseli) and Hummingbirds (Suborder Trochili), with Special Reference to their Relation to the Order Passeriformes. Transactions of the Zoological Society of London, 25(4):307-348, 4 plates. Milne-Edwards, A. 1871. Recherches anatomiques et paleontologiques pour servir a Vhistoire des oiseaux fossiles de la France. 4 volumes (1869-1871). Paris: Victor Masson et Fils. Paris, P. 1912. Oiseaux fossiles de France. Revue Frangaise d'Omithologie, 4(37):283-298. A New Osprey from the Miocene of California (Falconiformes: Pandionidae) Stuart L. Warter ABSTRACT Two nearly complete humeri and two partial ulnae from Barstovian age Miocene deposits at Shark- tooth Hill, near Bakersfield, Kern County, Cali? fornia, are described as the first known extinct spe? cies of the modern genus Pandion. Possible func? tional implications of the morphological differ? ences observed between the fossil species and modern P. haliaetus are discussed and the fossil record of the Pandionidae is reviewed. Introduction In 1973 an avian fossil owned by a private col? lector was brought for identification to the Natural History Museum of Los Angeles County (LACM) by Mr. Raj Guruswami-Naidu. T h e specimen, from the Miocene Sharktooth Hill beds, was identified by Dr. Hildegarde Howard and me as a right humerus closely resembling that of a modern osprey, Pan? dion haliaetus. The specimen was cast and re? turned, subsequently to be obtained anew by the collector and original owner, Mr. William Hawes, who donated it to the LACM, along with portions of a left humerus and parts of right and left ulnae that were found associated with it. Through the courtesy of Dr. Howard, Dr. Lawrence Barnes and Dr. David Whistler, all of the Department of Ver? tebrate Paleontology, LACM, the specimens were made available to me for study. Upon detailed comparison, the bones, which Stuart L. Warter, Department of Biology, California State University, Long Beach, California 90840, and Research As? sociate, Natural History Museum of Los Angeles County, Los Angeles, California 90007. bear a remarkable resemblance to those of modern Pandion haliaetus, were found to differ from that species in a number of subtle, but apparently sig? nificant features. These were considered suffii- ciently important to warrant recognition of a new species, thus extending the history of the genus Pandion back as far as the Miocene. The terminology used follows that of Howard (1929) and Fisher (1946). Twelve specimens of modern P. haliaetus were examined, four at the LACM and eight at the University of California, Los Angeles. Appreciation is expressed to the cu? rators of these collections for their cooperation. Detailed comparisons are based on skeleton LACM Bi 268, which is typical of larger specimens of P. haliaetus. Pandion homalopteron, new species FIGURES 1-3 HOLOTYPE.?Nearly complete left and right hu? meri and proximal portions of left and right ul? nae, all associated; LACM 42815; collected by Mr. William Hawes of Bakersfield, California. Right humerus entire, but shattered and filled in two places with plaster; surfaces of head and internal tuberosity sufficiently intact to permit reasonably accurate total measurement (151 mm), but other contours of both ends badly eroded; deltoid crest missing. Left humerus consisting of three pieces, plus fragments; shaft and distal end joined by ac? tual contact along external surface, proximal por? tion joined by comparison with companion right humerus and with left humerus of recent Pandion. Head of left humerus entire, but other contours of proximal end severely eroded; all articular sur? faces of distal end intact; only a small portion of 133 134 SMITHSONIAN CONTRIBUTIONS TO PALEOBIOLOGY a / * ? ***! FICURE 1.?Holotype humer i of Pandion homalopteron, new species (LACM 42815): a, pa lmar view and, fr, anconal view of left and r ight elements. Na tura l size. (Courtesy of Na tu ra l History Museum of Los Angeles County) base of deltoid crest remaining. Left ulna badly shattered, but nearly complete (180 mm), lacking approximately 20 mm or less of the distal end; proximal articular surfaces largely intait, tip of olecranon and tip of external cotyla broken. Right ulna less complete (120 mm) with proximal articu? lar surface largely intact, but olecranon, tip of in? ternal cotyla, and edge of external cotyla missing; distal 18 mm of shaft lacking the anconal surface, lasi 32 mm displaced to the palmar side and joined only by matrix. Colors variable: right humerus light tan; right ulnar fragment brown; left hu- NUMBER 27 135 a FIGURE 2.?Holotype humeri of Pandion homalopteron, new species (LACM 42815): a, external view and b, internal view of left and right elements. Natural size. (Courtesy of Natural History Museum of Los Angeles County) merus with proximal segment light tan, shaft and distal segment brown; left ulna brown proximally, fading to light tan distally. LOCALITY AND AGE.?From the Sharktooth Hill bone bed, middle Miocene (Barstovian age, Savage and Barnes, 1972:133). Round Mountain Silt, Sharktooth Hill, near Bakersfield, Kern County, California; LACM locality 3205. MEASUREMENTS OF HOLOTYPE.?See Table 1. The brachialis scar of the right humerus is 13 ? 2.5 mm long by 6 ? 1 mm wide (margin indistinct) and the length of the brachialis scar of the right 136 SMITHSONIAN CONTRIBUTIONS TO PALEOBIOLOGY TABLE 1.?Measurements (mm) of the holotype humeri (R = right; L = left) of Pandion homalopteron, new species, compared with modern P. haliaetus Character Total length Width of head from the external to the internal tuberosity.. Length from head to distal margin of deltoid crest Ratio of above measurement to total length (= % of total length) Width of shaft at distal end of deltoid crest Length of ectepicondyle from proximal margin of extensor metacarpi radialis to distal margin of flexor metacarpi radialis scar Length of entepicondyle from proximal margin of pronator brevis scar to distal margin of flexor carpi ulnaris scar .... Width of distal end P. homalopteron 151 (R) 27.5 (R) 63 (R&L) 41 12 (R & L) 14.5 (R&L) 12.5 (L) 24.5 (L) P. mean 145.9 27.1 63.3 42.9 11.5 15.8 14.6 23.8 haliaetus range 135-154 25-28.5 58-69 40-44 11-12 14.5-16.5 13-16 21.5-24.5 n 8 9 8 8 8 8 8 10 ulna is 30 mm. These measurements in P. haliae? tus are variable and may differ between the right and left sides of the same individual: the brachialis scar of the humerus ranges from 15 to 17.5 mm in length and 7 to 8.5 mm in width (n = 10); that of the ulna ranges from 28 to 36 mm in length (n = 10). DIAGNOSIS.?Pandion with humerus and ulna re? sembling those of large individuals of modern P. haliaetus, but showing evidence of weaker muscu? lature and other osteological features that prob? ably permitted less extension at the elbow and less rotation at the shoulder. ETYMOLOGY.?Greek homalos, even, level; and pteron, wing; referring to the more level configu? ration of the wing that would result from a reduced ability to raise the wrist during soaring, thereby reducing or eliminating the "kinked-wing" appear? ance often presented in flight by members of the modern species. DESCRIPTION.?Humerus with head more tri? angular, less rounded than in the modern form; capital groove and ligamental furrow shallower, less deeply excavated; anconal surface of internal tuberosity in internal view less tapering, more nearly perpendicular to main axis of shaft; capital groove and median crest not extending below pneumatic foramen as they do in P. haliaetus. Distal end of humerus with internal condyle higher, more rounded than in P. haliaetus; ole- cranal fossa in palmar-distal view shallower and wider; border of fossa in anconal-distal view less rounded, more triangular; brachial depression noticeably smaller and less excavated, its external margin situated more externally; external condyle in palmar view rotated, its long axis at a greater angle from the axis of the shaft; viewed from the external side the external condyle rounder, less squared, and less deep than in the modern form. Ectepicondylar and entepicondylar prominences shorter, the scars for M. extensor metacarpi radi? alis and M. pronator brevis closer to the distal end of the bone; facet of anterior articular ligament wider and shorter, its surface flat to concave, this facet in P. haliaetus being longer, narrower, and convex. Proximal end of ulna with surface of internal cotyla shallower, its lip (palmar surface) more ex? tensively flared; palmar lip of radial depression less enlarged; surface of external cotyla less angled from the axis of the shaft, more steeply inclined from the surface of the internal cotyla; scar for the insertion of M. brachialis ( = M. brachialis anti? cus) shorter than in most modern specimens of equivalent size; prominence for anterior articular ligament with shorter, wider facet; proximal half of radial surface of ulna convex in cross-section, whereas flattened or concave in the modern form; olecranon apparently less robust. Discussion The modern Osprey, Pandion haliaetus, is a highly specialized fish hunter. It is capable of hov? ering over one spot with rapidly beating wings held high over the back. Also, it is capable of increasing NUMBER 27 137 a b FIGURE 3.?Holotype ulnae and humerus of Pandion homalopteron, new species (LACM 42815): a, dorsal view and b, palmar view of left and right ulnae; c, distal end of left humerus in distopalmar view. Natural size. (Courtesy of Natural History Museum of Los Angeles County) I: SMITHSONIAN CONTRIBUTIONS TO PALEOBIOLOGY the angle of attack of the wings in level soaring flight by raising the wrists through rotation of the long outstretched forelimbs. In this position the wings present the "kinked" or "crooked" appear? ance for which it is so well known. The distinctive shape of the deltoid crest of P. haliaetus is undoubtedly related to the aforemen? tioned abilities. It is a large, triangular plate, de- flexed from the external surface in a palmar direction and beginning abruptly at a point more distad than in other falconiforms. While the del? toid crest is missing from both humeri of P ho? malopteron, enough remains of the base of the crest of the left humerus to tell that the entire process was similarly positioned, enlarged and de- flexed (Figure 1). A large deltoid crest usually is indicative of strong pectoral musculature and well-developed powers of flight. Perhaps paradoxically, such a crest occurs in Pandion along with a rounded sternal carina, a feature that in soaring birds like cathar- tid vultures often is associated with a small deltoid crest and a relatively weak flight mechanism. In Coragyps (Fisher, 1946:603), the palmar surface of the deltoid crest provides the area of insertion of the superficial layer of M. pectoralis ( = pectoralis superficialis), and on the anconal surface of the crest, M. deltoideus minor and M. deltoideus major originate on the crest and on extensive areas of the shaft of the humerus proximal, distal, and posterior to the deltoid crest. Judging from muscle scars on the humerus of P. haliaetus, however, the enlarged deltoid crest serves as the area of insertion for much, if not all, of the large M. deltoideus major, whereas M. deltoideus minor is small and inserts anconally along the shaft anterior to the crest. In Coragyps, the anterior portion of M. deltoi? deus major "is more important in elevating the leading edge of the wing since the anterior exten? sion of the deltoid crest provides a longer lever arm" (Fisher, 1946:590). An important function of the expanded, deflexed, deltoid crest in Pandion, then, is to provide a lever arm for increasing the upward rotational ability of the humerus through the action of M. deltoideus major. A similar in? crease in downward rotational ability would prob? ably be conferred to the humerus by M. pectoralis. The humerus of Pandion also has an enlarged internal tuberosity, the function of which is to in? crease the lever arm for several small muscles in? serting upon it which, in vultures (Fisher, 1946: 603), serve to depress the trailing edge of the wing, thereby raising the leading edge. The described differences in the humeral head, capital groove, ligamental furrow, and internal tuberosity of P. homalopteron may indicate a lesser degree of mus? cular development and rotational ability in the shoulder than in P. haliaetus. The differences in the morphology of the elbow joint provide additional evidence of some degree of functional dissimilarity between the two species of Pandion. The configuration of the joint surfaces would seem to indicate a lesser degree of extension at the elbow in P homalopteron. This appears to be borne out by mechanical manipulation of the bones. The forearm of P. haliaetus exhibits a much greater degree of extension at the elbow than does that of Buteo. The robust olecranon of P. haliaetus fits closely into its corresponding depression on the humerus, possibly serving as a bony stop against further extension. The degree of this extension in P. homalopteron is also greater than in Buteo, but less than in P. haliaetus. In spite of the olecranon being incomplete, the ulna of P homalopteron could not be extended to the same degree as that of P. haliaetus without partially disarticulating the joint. The observed differences in the size and con? figuration of the attachment for the anterior ar? ticular ligament also might be related to the de? creased ability to extend the elbow. In the fossil form, the convex radial surface of the ulna, the smaller M. brachialis scars, and pos? sibly the more distal origins of Mm. pronator brevis and extensor metacarpi radialis, may indicate weaker intrinsic musculature. All three of the above muscles are involved in flexion of the forearm, while Mm. brachialis and pronator brevis also are in? volved in supination and pronation, respectively, of the manus (Fisher, 1946:591-594). Intrinsic rotational movements of the hand and forearm in birds are limited (Bellairs and Jenkin, 1960:258), and the degree to which they occur has not been determined (George and Berger, 1966: 14). However, P haliaetus may have greater abili? ties to raise the wrist through intrinsic rotation, as well as by rotation at the shoulder of an entire, more extended wing, than did P. homalopteron. There is no reason to assume that P. homalop? teron was any less variable in its dimensions than is modern P. haliaetus. T o the extent that the NUMBER 27 139 single available specimen can be considered typical of the Miocene population, the species P. homalop? teron appears to have been larger in absolute gross skeletal dimensions than an average-sized modern Osprey, but was smaller than average in other measurable features. Several of these features may indicate a lighter wing musculature relative to bone size than is found in P. haliaetus. This, along with the seemingly lesser powers of extension and rotation of the wing, presents a picture of a bird similar to the modern Osprey in size, but one with a more level wing and less refined powers of soaring and hovering. Such a bird could be ancestral to P haliaetus. The Fossil Record of the Pandionidae Pandion homalopteron provides the only Ter? tiary record of the family Pandionidae founded on adequate and diagnostic material. Brunet (1970) has placed the species Palaeocircus cuvieri Milne- Edwards, based primarily on an incomplete carpo? metacarpus from the upper Eocene of France, in the Pandionidae, stating that the type, while spe? cifically distinct, is scarcely separable from Pan? dion at the generic level. Storrs Olson (pers. comm.) believes that Brunet's illustrations of the specimen indicate to the contrary, however, since both the proximal and distal symphyses between metacarpals II and III are longer than in Pandion. The assignment of Palaeocircus to the Pandionidae should be regarded with caution, particularly since the family is at present monotypic and the addi? tion of another genus would require redefinition of the family. A record of Pandion from the middle Pliocene Bone Valley Formation in Central Florida (Brod? korb, 1972) is based on a single claw (Storrs Olson, pers. comm.). Another claw, kindly lent to me by the National Museum of Natural History, Smith? sonian Institution, (USNM 192193), comes from the Lee Creek phosphate mine near Aurora, Beau? fort County, North Carolina. Middle Miocene and Pliocene fossiliferous deposits are exposed there, and in this case it is not certain from which level the specimen was derived (Storrs Olson, pers. comm.). This claw is from digit III of the right foot, but has the tip broken so that an accurate measurement of the chord is not possible. It is ref? erable to the genus Pandion and is of a size ap? propriate for either P. homalopteron or P. haliae? tus, but since this element is not diagnostic and its age is uncertain, no specific identification can be made. The only other fossil records for the Pandionidae are Pleistocene remains of the modern species Pandion haliaetus. T o the various localities listed in Brodkorb (1964:260) may be added a pre? viously unreported left tarsometatarsus (LACM 27082) from Pleistocene deposits at Kelly Springs, Kelly Park, Orange County, Florida (LACM lo? cality 7119). Literature Cited Bellairs, A. D*A., and C. R. Jenkin 1960. The Skeleton of Birds. Pages 241-300 in Volume 1 of A. J. Marshall, editor, The Biology and Com? parative Physiology of Birds. New York: Academic Press. Brodkorb, P. 1964. Catalogue of Fossil Birds, Part 2 (Anseriformes through Galliformes). Bulletin of the Florida State Museum, Biological Sciences, 8(3): 195-335. 1972. New Discoveries of Pliocene Birds in Florida [Ab? stract]. Page 64 in Proceedings of the XVth Inter? national Ornithological Congress. Leiden: E. J. Brill. Brunet, J. 1970. Oiseaux de l'?ocene Sup^rieur du Bassin de Paris. Annates de Paleontologie (Vertebres), 56(1): 1-57, 4 plates. Fisher, H. I. 1946. Adaptations and Comparative Anatomy of the Locomotor Apparatus of New World Vultures. American Midland Naturalist, 35(3):545-727, 28 figures, 13 plates. George, J. C, and A. J. Berger 1966. Avian Myology, xii + 500 pages. New York: Aca? demic Press. Howard, H. 1929. Avifauna of the Emeryville Shellmound. University of California Publications in Zoology, 32(2):301- 394, 54 figures. Savage, D. E., and L. G. Barnes 1972. Miocene Vertebrate Geochronology of the West Coast of North America. Pages 124-145 in E. H. Stinemeyer, editor, Proceedings of the Pacific Coast Miocene Biostratigraphic Symposium. 364 pages. Bakersfield, Cal.: Society of Economic Paleontolo? gists and Mineralogists. A New Species of Flightless Auk from the Miocene of California (Alcidae: Mancallinae) Hildegarde Howard ABSTRACT Praemancalla wetmorei is described from the late Miocene of Orange County, California, with hu? merus and ulna as holotype and paratype, and radius, carpometacarpus, and coracoid referred. The species, although less specialized as a flightless diver than the geologically younger genus Man- calla, appears to be more advanced then Praeman? calla lagunensis, which is believed to be derived from slightly older deposits. Introduction Since Lucas (1901) described the first humerus of Mancalla, knowledge of the flightless mancalline alcids (Mancallinae) has increased to include nearly all skeletal elements and to involve five spe? cies and two genera. The type-genus, Mancalla, is known from four species?M. californiensis Lucas (1901), M. di- egense (Miller, 1937), M. milleri Howard (1970) and M. cedrosensis Howard (1971)?and is recorded from Humboldt County in northern California to Cedros Island, Mexico. The Humboldt County site, with a single humerus assigned to M. diegense (Howard, 1970), is believed by Kohl (1974:217) to be Pleistocene in age. T h e other records are middle to late Pliocene. Praemancalla is known from the single species, P. lagunensis Howard (1966), de- Hildegarde Howard, Chief Curator Emeritus, Natural His? tory Museum of Los Angeles County, 900 Exposition Blvd., Los Angeles, California 90007. scribed from a late Miocene deposit in Leisure World, Laguna Hills, Orange County, California. Recently, three other Miocene sites in Orange County have yielded mancalline bones. These sites are in Laguna Niguel, approximately 5 km south of the Laguna Hills locality. The specimens from these sites are in the collections of the Natural His? tory Museum of Los Angeles County. The catalog and locality numbers are listed under Los Angeles County Museum (LACM). The associated avifauna from these sites includes the same families recorded at the type-locality of Praemancalla lagunensis (LACM Loc. 1945), but the species represented are not identical. None of the species described as new from locality 1945 has appeared in the Laguna Niguel localities. On the basis of associated marine mammals, it is suggested that these sites may represent a later subdivision of the late Miocene than locality 1945 (Barnes, et al., in prep.). T h e mancalline skeletal elements from Laguna Niguel include humerus, ulna, radius, carpometa? carpus, and coracoid, all of which have been pre? viously described for Mancalla. Only for the carpometacarpus, coracoid, and distal end of the humerus is there comparable material of Praeman? calla. The newly found specimens suggest a gen? erally larger form than any previously described mancalline species. Qualitative characters show dis? tinction from comparable elements of all species of Mancalla. Distinctions are also apparent with re? spect to Praemancalla lagunensis, but the degree of adaptation towards restriction of the wings for swimming is closer to Praemancalla than to Man? calla. Possibly a third genus is indicated. At the 141 142 SMITHSONIAN CONTRIBUTIONS TO PALEOBIOLOGY present state of knowledge, however, it seems wiser to assign the specimens to the genus Praemancalla under a new species name. ACKNOWLEDGMENTS.?I am grateful to the Earth Sciences Division of the Natural History Museum of Los Angeles County for placing the museum's collections at my disposal and for the many cour? tesies of the staff members. I particularly appre? ciate the assistance of Dr. Lawrence Barnes in dis? cussion of matters pertaining to the field work in Orange County. The photographs were taken by Lawrence Reynolds, museum photographer. Spe? cial thanks go to my husband, Henry Anson Wylde, for the art work in connection with the prepara? tion of the plate. Praemancalla Howard In describing Praemancalla lagunensis, the spe? cific diagnosis of the holotype humerus and para? type carpometacarpus served also as the generic diagnosis. In the specimens from Laguna Niguel now at hand, the following characters are in agree? ment with that diagnosis: Humerus with groove separating base of ectepi? condyle from external condyle, brachial impres? sion faint and running diagonally from ectepi? condylar prominence to a point slightly proximal to attachment of articular ligament, with no pap? illa present above condyles. The tricipital grooves and ridges are broken in the humerus from Laguna Niguel, so the characters of this area set forth in the original diagnosis cannot be assessed. Carpometacarpus with distinct, blunt pisiform process, trochlear area having narrow, deep groove between internal and external crests posteriorly, metacarpal II relatively broad with more rounded anterior contour and more angular internal con? tour than in Mancalla, and process of metacarpal I relatively shorter. The following additional characters observed in the specimens now at hand are considered to be of generic value when compared with Mancalla: hu? merus with head only slightly extended over capi? tal groove, deltoid crest weakly developed, area of anterior articular ligament slightly swollen; ulna with prominent olecranon process; radius lacking prominent crest on convex contour; coracoid with scapular facet facing dorsally, coracohumeral at? tachment flat and angular in outline. Praemancalla wetmorei, new species FIGURE la, b, e-g, i-k HOLOTYPE.?Humerus, LACM 42653, complete except for tricipital area of distal end (Figure TYPE-LOCALITY.?LACM Loc. 6906, site of exca? vation for North American Rockwell building (now U.S. General Services Administration build? ing) on El Lazo Road, Laguna Niguel, Orange County, California; 914 m north of junction of Aliso Creek and Sulfur Creek, in yellow sands and laminated gray shale. Latitude 33?33'43" N, longi? tude 117?42'44" W. In the NE 1/4 NE 1/4 SE 1/4 of unsurveyed Sec 16, T7S, R8W, San Juan Capistrano quadrangle, USGS 1948, 1:24000. FORMATION AND AGE.?Monterey Formation, late Miocene. PARATYPE.?Proximal end of ulna LACM 32429 from type-locality (Figure \e). DIAGNOSIS.?Humerus broad proximally; medial profile of capital groove a wide open curve; depth through deltoid crest only 5 percent greater than depth of shaft above distal end; ectepicondylar prominence notably protuberant at its proximal tip and slightly lateral in position with respect to palmar surface of shaft; groove between external condyle and base of ectepicondyle more constricted and less distal in extent than in P. lagunensis; shaft breadth above ectepicondylar prominence 53 percent of shaft depth at same point; shaft depth 113 percent of breadth of distal end. Ulna laterally compressed, with short brachial impression partially palmad in position and bor? dered palmad by heavy ridge; olecranon blunt but protruding proximally beyond cotylae and dis? tinctly set off from cotylae by lateral depression both externally and internally. MEASUREMENTS.?Humerus: length to external condyle 82.7 mm, greatest proximal breadth from pectoral to bicipital crests 22.2 mm, breadth across head 19.6 mm, breadth through distal condyles 8.5 mm, breadth and depth of shaft above ectepi? condylar prominence 5.1 mm and 9.6 mm, respec? tively, height of ectepicondylar prominence above distal end 16.9 mm, greatest depth through deltoid crest 10.1 mm, breadth of shaft at same point 5.5 mm. Ulna: proximal breadth across cotylae 7.5 mm, proximal depth through olecranon 11.3 mm, NUMBER 27 143 ' b -???--, FIGURE 1.?Skeletal elements of Praemancalla and Mancalla: a, b, coracoid (LACM 37637) of P. wetmorei, new species, medial and dorsal views; c, coracoid (LACM 15289) of P. lagunensis, dorsal view; d, coracoid (LACM 2310) of M. diegense, dorsal view; e, paratype ulna (LACM 32429) of P. wetmorei, internal view; /, referred carpometacarpus (LACM 52216) of P. wetmorei, internal view; g, radius (LACM 53907) of P. wetmorei, palmar view, h, humerus (LACM 15367) of M. cedrosensis, palmar view; i, j , holotype humerus (LACM 42653) of P. wetmorei, palmar and anconal views; k, referred humerus (LACM 32432) of P. wetmorei, anconal view; /, humerus (LACM 2331) of M. diegense, anconal view. (Approximately natural size.) 144 SMITHSONIAN CONTRIBUTIONS TO PALEOBIOLOGY breadth and depth at middle of shaft 4.2 mm and 6.2 mm respectively. REFERRED MATERIAL.?From Laguna Niguel, Orange County, California, late Miocene, Mon? terey Formation. Proximal end of humerus LACM 32432 (Figure Ik) from type-locality (LACM Loc. 6906). Complete radius LACM 53907 (Figure lg) and scapular end of coracoid LACM 37637 (Figure \a,b) from LACM locality 6902 at northwest end of El Lazo Road, 365 m northwest of type-locality and 244 m east of Aliso Creek, in basal 0.5-1.5 m of coarse yellow sand directly overlying laminated gray shale. Proximal y4 of carpometacarpus LACM 52216 (Figure If) from LACM locality 3185, in tributary gully west of Aliso Creek in coarse yellow sand. ETYMOLOGY.?I take pleasure in naming this new species in honor of Dr. Alexander Wetmore, who has done so much to further the science of pale? ornithology and who has generously given advice and counsel to me throughout my years of study in this field. DESCRIPTION.? Compared with Mancalla, the hu? merus of P. wetmorei is relatively, as well as ac? tually, broader both proximally and distally (ratio of greatest proximal breadth to length 26.8 percent in P. wetmorei, 23-25 percent in Mancalla; ratio of distal breadth to length 10.2 percent in P. wet? morei, 8.2-9.6 percent in Mancalla) and exceeds in length all but one specimen of Mancalla (the maxi? mum of M. diegense). It is, however, 8 percent longer than the average for M. diegense and 12 percent longer than the average for M. cedrosensis (Table 1), and 32 percent longer than the much smaller M. milleri. The lesser protrusion of the head over the capi? tal groove is reflected in the wide, open curve be? tween the head and internal tuberosity as seen in palmar and anconal views; this condition contrasts with the narrow, U-shaped curve found in Mancalla (Figure \h-l). Further distinction from Mancalla is seen in the deltoid crest which, in P. wetmorei, de? scribes a low, even arc and is not expanded towards its distal termination. Distally, the greater breadth of the humerus is observed not only in the width through the condyles but also in a slight expansion in the region of the attachment of the anterior lig? ament. In this character, as well as in the lateral slant of the brachial impression and absence of a prominent papilla above the condyles, P. wetmorei resembles Praemancalla lagunensis. It is distin? guished from that species in the greater projection of the ectepicondylar prominence from the shaft, narrower groove between the base of the ectepi? condyle and external condyle, and relatively nar? rower and deeper shaft (relative breadth to depth of shaft 53 percent in P. wetmorei, 66 percent in P. laguensis). In depth of shaft relative to breadth of distal end, P. wetmorei is intermediate between Praemancalla lagunensis and the several species of Mancalla (99 percent in P. lagunensis, 113 percent in P. wetmorei, 126-140 percent in Mancalla). T h e prominence of the olecranon immediately distinguishes the ulna of P. wetmorei from all spe? cies of Mancalla, but the palmad position of the brachial impression and the shortened lip of the external cotyla assign the element to the subfamily Mancallinae rather than the typical alcids. The radius (LACM 53907), although short and laterally compressed as in Mancalla, is less blade? like and lacks the prominent crest on its convex contour. The ulnar depression is broader and deeper than in Mancalla. Neither the ulna nor the radius is known for Praemancalla lagunensis. Those assigned to P. wetmorei both show less modi? fication towards a flipper-like wing than in Man? calla, and in this regard are in keeping with the character of the other elements known for Praemancalla. The radius is 12 percent longer than the maxi? mum known for any species of Mancalla (Table 1). Using the radius as a guide, and comparing the relative size of ulna to radius in the type of Man? calla cedrosensis (associated skeletal elements of one individual), it is suggested that the ulna of P. wetmorei attained a length of 36.5 mm. Carpometacarpus LACM 52216 differs from that of Mancalla and resembles Praemancalla in the presence of a distinct, blunt pisiform process, rounded anterior contour of shaft of metacarpal II and deep narrow groove between the internal and external crests of the trochlea posteriorly. It is distinguished from P. lagunensis by the narrower shaft and the relatively longer process of meta? carpal I, with more than half its length distal to the level of the metacarpal symphysis; also, the troch? lea extends higher above that process and the lat? eral surface of the internal crest of the trochlea is more broadly and less deeply depressed. In coracoid LACM 37637 the furcular facet is NUMBER 27 145 TABLE 1.?Skeletal measurements (mm) of Praemancalla wetmorei compared with P. lagunensis, Mancalla diegense, M. cedrosensis, M. californiensis Character H U M E R U S Length Greatest p rox imal b read th Distal b r ead th U L N A Proximal d e p t h .... Proximal b read th .. RADIUS Greatest length Greatest shaft d e p t h Shaft b read th CARPOMETACARPUS Length process Metacarpal I Proximal d e p t h .... Shaft b read th CORACOID Length from below scapular facet to head Bread th below furcular facet . . Breadth furcular facet P. wetmorei 82.7 22.2 8.5 11.3 7.5 35.8 5.8 3 15.7 12.1 4.3 20.9 5.8 10.3 P . lagun? ensis 7.8 _ 14 11.9 4.5 18.8 6 M. m i n . 71 17.3 6.4 9 t 5.9 29.6 6.3 2.3 15.2 9.7 3.1 15.4 5.4 7.3 diegense mean 76.5 18.7 6.7 6.4 30.9 6.35 2.5 15.3 10.3 3.4 17.3 5.8 7.8 max . 85.2 20.3 8 9.3 6.6 31.8 6.4 2.7 15.5 11 3.7 19.5 6.3 8.6 M . min . 69.5 17 6.9 8.8 6.2 27.3 5.4 2.5 15.4 10.2 3.4 15.2f 5.2 7.1f cedrosensis mean 73.5 17.9 7 9.7 6.6 29.3 5.6 2.6 15.6 10.5 3.5 5.5 max . 80 20.1 7.2 10.2 7.2 31.1 6.1 2.8 16 11.1 3.8 16.7 6 7.3 M. cali? forniensis* 19.4 9.9 6.5 29.7 6.8 2.3 17.1 11.2 3.4 18.8 5.9 8.7 * Only one specimen of each element of M. californiensis, except carpometacarpus (average of four). f Only two specimens measurable for this dimension. broad and deep; it extends ventrally well beyond the triosseal canal, is strongly thrust mediad above the canal, and is markedly undercut. Below the facet the bone narrows and the ventral border of the triosseal canal is sharply angular. T h e species of Mancalla vary in development of the furcular facet and the bordering of the triosseal canal. T h e greatest overhang of the facet and the least angu? lar border of the triosseal canal are found in M. cedrosensis; the least overhang and most angular border of the canal occur in M. californiensis. In no specimen of Mancalla is the furcular facet as ventrally extended as in P. wetmorei. This facet is broken ventrally in the single known coracoid of P. lagunensis, but the portion that remains is deep and has a strong overhang; below the facet, how? ever, the area is broader and more rounded than in P. wetmorei. In direct dorsal view (with dorsal surface of shaft held horizontally) the scapular facet in P. wetmorei is more dorsally and less lat? erally directed than in Mancalla, and the triosseal canal faces more mediad. Resemblance is closer to Praemancalla lagunensis, although the canal is even more medially directed in the latter species. The attachment of the coracohumeral muscle in P. wetmorei is broad, flat, and angular in outline at its anterior end, as in P. lagunensis, but is rela? tively longer, and narrows near the glenoid facet. In Mancalla the attachment is narrow and rounded. 146 SMITHSONIAN CONTRIBUTIONS TO PALEOBIOLOGY Conclusions Four wing elements and a coracoid from three correlative localities of late Miocene age in Laguna Niguel, Orange County, California, represent a new species, Praemancalla wetmorei, in the alcid subfamily Mancallinae. The degree of specializa? tion towards a flipper-like wing is less than in the Pliocene genus Mancalla, and reflects a stage of development closer to the Miocene genus Prae? mancalla. Differences noted with respect to Prae? mancalla lagunensis, however, suggest a slight advance towards the more specialized wing of Mancalla. T h e humerus is more compressed, the triosseal canal of the coracoid more dorsally ro? tated and narrower, and the process of metacarpal I of the carpometacarpus longer. This suggested evolutionary trend is in keeping with the evidence presented by the associated faunas of the localities involved, which indicates a slightly greater age for the type-locality of P. lagunensis than for the Laguna Niguel sites. Literature Cited Barnes, L. G., D. P. Domming, H. Howard, R. W. Huddles- ton, and C. A. Repenning In prep. Correlation and Characterization of Late Mio? cene (Clarendonian Correlative) Marine Vertebrate Assemblages in California. Howard, Hildegarde 1966. A Possible Ancestor of the Lucas Auk (Family Mancallidae) from the Tertiary of Orange County, California. Los Angeles County Museum Contri? butions in Science, 101:1-9, 1 figure, 2 tables. 1970. A Review of the Extinct Avian Genus Mancalla. Los Angeles County Museum Contributions in Science, 203:1-12, 1 figure, 4 tables. 1971. Pliocene Avian Remains from Baja California. Los Angeles County Museum Contributions in Science, 217:1-17, 2 figures, 1 table. Kohl, Roy F. 1974. A New Late Pleistocene Fauna from Humboldt County, California. Veliger, 17(2):211-219, 2 maps, 1 table. Lucas, Frederic A. 1901. A Flightless Auk, Mancalla californiensis, from the Miocene of California. Proceedings of the United States National Museum, 24(1245): 113-134, 3 figures. Miller, Loye 1937. An Extinct Puffin from the Pliocene of San Diego, California. Transactions of the San Diego Society of Natural History, 8(29): 375-378, 2 figures. The Pleistocene Pied-billed Grebes (Aves: Podicipedidae) Robert W. Storer ABSTRACT Pleistocene specimens of pied-billed grebes (Podi- lymbus) were compared with a series of skeletons of the modern North American form, Podilymbus podiceps podiceps. Most of the fossils agreed closely with this form and are allocated to it. T h e co-types of Podilymbus magnus Shufeldt also fall within the range of variation of this form, hence P. magnus becomes a synonym of P. podiceps. A new species, Podilymbus wetmorei, characterized by a wide tar? sometatarsus and a heavy femur, is described from the Pleistocene of Florida. Introduction The Pied-billed Grebe (Podilymbus podiceps) is widely distributed in the New World from Canada to southern South America. T h e only other living species of the genus, the Atitlan or Giant Pied- billed Grebe (P gigas), is confined to Lake Atitlan, Guatemala. T h e genus is represented in upper Pliocene deposits of Idaho by a large species, P. majusculus (Murray, 1967), and in numerous Pleistocene deposits. Most of the Pleistocene specimens have been assigned to the living species, P. podiceps, but a few have been referred to an allegedly larger extinct species, P. magnus. T h e latter was first described by Shufeldt (1913:136- 137) on the basis of two tarsometatarsi and a cora? coid from Fossil Lake, Oregon. Later, Wetmore (1937:198-199) synonymized P. magnus with P. podiceps, pointing out that there is considerable Robert W. Storer, Museum of Zoology, The University of Michigan, Ann Arbor, Michigan, 48104. sexual dimorphism in the genus and that Shufeldt had only one skeleton (a female) of the living spe? cies with which to compare his fossil material. Wet? more found that the larger of the tarsometatarsi described by Shufeldt was only slightly larger than those of two males of the living North American subspecies (P. p. podiceps) and was matched by an example of the slightly larger South American race (P. p. antarcticus). More recently, Brodkorb (1959: 273-274) revived the name P. magnus for twelve bones from Arredondo, Florida, using eight skele? tons of the living North American form for com? parison. He (1963a: 113) also referred material from the Santa Fe River, Florida, to P. magnus. McCoy (1963:337) in his report on the fossil avi? fauna of the Itchtucknee River, a tributary of the Santa Fe, referred two tarsometatarsi to P. magnus and 47 other bones (including two other tarsometa? tarsi) to P. podiceps. Subsequently, Brodkorb (1963b:230) wrote that "specimens from Fossil Lake and some of the Floridian localities average large and are perhaps recognizable as a temporal subspecies, Podilymbus podiceps magnus Shufeldt." T h e availability of a series of 39 skeletons of the modern North American form (Podilymbus p. podiceps) from Michigan and Wisconsin has per? mitted a better estimate of variation within a living population of this species than was heretofore pos? sible, as well as providing a comparison of skeletal elements of this population with a large number of fossil elements from late Pleistocene deposits. T h e following fossil material has been examined:Cali? fornia: McKittrick, 1 tarsometatarsus; Rancho La Brea, 1 femur; Florida: Reddick, 3 coracoids, 1 humerus, 1 tibiotarsus, 2 tarsometatarsi; Haile, 1 coracoid, 1 ulna, 1 tibiotarsus; Arredondo, 2 cora? coids, 3 humeri, 1 ulna, 3 carpometacarpi, 1 femur, 147 148 SMITHSONIAN CONTRIBUTIONS TO PALEOBIOLOGY TABLE 1.- Character ?Measurements (mm) of modern and late Pleistocene Pied-billed Grebe bones MODERN FOSSIL n max. min. mean?<7ra a n max. min. mean?