OCCURRENCE OF THE CRINOID GENUS APIOCRTNUSIN AMERICA
By Frank Springer,Associate in Paleontology, United States National Museum
The genus Apiocrmus is one of the most conspicuous of Mesozoiccrinoids, hitherto known only from Europe, where it is found as <itypical fossil in the upper Jurassic (Oolite) of England, France,and Switzerland. It was first described and figured by Parkinson 1under the name " Pear Encrinite," in allusion to the pronounced pearshape of the calyx. In 1820 Schlotheim designated Parkinson'sspecies according to the rides of binomial nomenclature as Encrinitesparkinsoni, nearly all crinoids then being known as Encrinites.In the following year J. S. Miller in his Natural History of theCrinoidea, 1821, proposed the genus Apiocrinus for the Parkinsonfossil, to which he gave a new specific name, A. rotundus; this wasnot accepted because clearly a synonym of Schlotheim's species.Thus the name became established as Apiocrinus (Apiocrinites)parkinsoni (Schlotheim) for the species by which the genus is bestknown in collections, through specimens from the Bradford clayof England, and from various localities in England and France.The genus is abundant and widely distributed, 27 species havingbeen described, 15 from France, 2 from England, and 10 fromSwitzerland and adjacent regions. The descriptions of most of themmay be found in the works of D'Orbigny, Quenstedt, and De^Loriol.Apiocrinus is the type of a very distinct family which has con-tinued from the Jurassic to the present time; and the genus itself,in its typical forms, is strongly differentiated from its fellows bythe fact that the stem, which is round and without cirri, is in itsupper part greatly expanded into a proximal conical enlargementcontinuous with the sides of the calyx, so that there is no line ofdemarcation between them. Its characters in detail are well shownin the figures of A. parkinsoni in Zittel-Eastman's Text-book of
1 Organic Remains of a Former World, 1808. vol. 1, p. 208, pi. 16, figs. 1-8, fromBradford, near Batli, England.No. 2590.
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Proceedings U. S. National Museum, Vol. 67, Art. i8.21513?25 1
2 PROCEEDINGS OF THE NATIONAL MUSEUM vol. GTPaleontology " ; while the general aspect of the fossil is illustratedon page 231 by their copy of D'Orbigny's restoration, incorrect asto cirri, of his well known species, A. roissyanus; also in Dana'sManual of Geology. 3While remains of five other important European Mesozoic genera,Pentacrinus, Isocrinus, Balanoaiivus, Bourgueticrinus, and Mar-supites, have been identified in America, the extremely prolific Apio-crinus has remained until this time unrepresented in the westernhemisphere. I am now able to announce its addition to the list.In March. L923, Mr. W. S. Adkins brought into the United StatesNational Museum in Washington a series of fossils collected by himin the course of geological investigations for the Cia. Mexicana dePetroleo " El Aguila " on the isthmus of Tehuantepec, Mexico.Among them were a number of crinoid stem-fragments which weresubmitted to me for examination. Some of these were in the matrix,a pinkish limestone, and others loose. They were derived from alimestone outcrop on the east bank of the Rio Plaj^as at a point 10.8kilometers south and 3.9 kilometers east of the northeast corner ofthe Limantour property, near the junction of the rivers Playas andPotrero Nuevo. The horizon was identified by Mr. Adkins, on thestrength of the other fossils, as upper Jurassic or lower Cretaceous,probably the former, which the evidence of the crinoids confirms.The crinoid stems are in small sections, none of them containingmore than eight or ten columnals. In several the joint-faces arewell exposed, and inspection of them at once eliminated Pentacrinus.and Balanocrinus from consideration, while it disclosed a similarityof type to the joint-faces of Apiocrinus, which was confirmed by thepresence of a single piece containing five, columnals having the char-acteristic expansion of the stem proximal to the calyx. This left nodoubt as to the generic affinity of the fossils, thus establishing forthe first time the existence of Apiocrinus in the rocks of the Ameri-can continent. While the material is too imperfect for close specificdiscrimination, the occurrence is of sufficient interest paleontologi-es Uy to warrant the designation of a new species, for which I pro-pose the name
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APIOCRINUS TEHUANTEPEC. new speciesThere ate about 20 stem-fragments, similar in appearance andevidently belonging to the same species; all are round, and withouttrace of cirri, the largest about 10 mm. in diameter. The taperingspecimen is the most characteristic. Its five columnals have a totallength of 13 mm., and during that interval it enlarges from 7 mm.to 10. The joint-face is marked by about 56 fine radiating striae
M'.h:: edition, i>i>. 230, 231. s Fourth edition, p. 77*.
aht. 18 THE CRIXOIJ) GENUS A.PIOCRINUS SPRINGEK &running inward from the periphery to a smooth ring surroundingthe lumen, about one-third the diameter of the columnal and flushwith ..the adjacent surface; this is seen in several specimens, and isevidently a constant character, with perhaps some variation in rela-tive diameter.In the structure of the joint-face may be seen the decisive differ-ence between this genus and Pentacrinus, Isocrinus, or Balanocrinus,the other forms which might be encountered in rocks of the same age.In these the joint-face is divided into five petaloid sectors differingamong the genera, the first two having short crenelations at the mar-gin of the sectors, and the last having them only at the periphery ofthe stem. In Apiocrinus there are no sectors, and the striae extenddirectly inward for about one-third to two-fifths the diameter ofthe joint, or perhaps sometimes all the way to the lumen. For con-venience of comparison with the Apiocrinus joint-face, and also tofacilitate identification of fragments that are likely to be found, Iam giving characteristic figures of the other two types (pi. 1, figs.8, 9, 10, 11). The smooth ring surrounding the lumen is a markedcharacter in our species, occupying about one-third the diameter ofthe joint, probably varying in different parts of the stem; it is butlittle, if any, sunken below the general surface of the joint, and thestriae in some cases pass over it.Among European species comparison may be made with Apio-crinus elegans (Defrance), which is of a very similar type to ourspecies, having usually less curvature to the sides of the expandedstem than in such characteristic species as A. parhinsoni and A.roissyanus. Apiocrinus elegans was described by Defrance in1819 4 as Astropoda, and in 1839 was referred by D'Orbigny toApiocrinus:' The species is widely distributed, and occurs at manylocalities in France, especially in the districts of Calvados, Coted'Or, Nievre, etc. It has been thoroughly described and figured byDe Loriol,6 from whom I am giving copies of his figures 1, 4, and 6of plate 34, showing the contour of stem and calyx, and figures 4,46, 4<? of plate 35, giving details of the joint-face.In relative proportions of the corresponding parts there is littledifference between our species and this. In the 5 columnals of oursthe spread in diameter is as 1 to 1.4; in De Loriol's figures of A.elegans on plate 34 for the same number of columnals the spread infigure 4 is as 1 to 1.5, and in figure 6 as 1 to 1.6. The joint-face asshown by figures 4, 4c of plate 35, has a somewhat less number ofstriae, about 48, and a similar smooth median ring, which is rela-tively larger and distinctly sunken. This smooth inner ring sur-
?Dict. des Sci. Nat., vol. 14, p. 468.6 Hist. Nat. des Crinoides, p. 29, pi. 5, figs. 9-15.
? Crinoides de la France, vol. 2. pt. 1, 1888, p. 240, pis. 34, 35.
4 PROCEEDINGS OF THE NATIONAL MUSEUM YOL. 67rounding the lumen seems to be a constant feature in Apiocrinus, aswell as in some other genera, as for instance, Prolsocrinus A. H.Clark 7 a Recent member of the same family. It varies fromstrongly marked and deeply sunken to flush with the rest o'f thesurface. So far as can be ascertained, it seems to be most marked atthe top of the stem just beneath the conical enlargement, graduallybecoming less marked and finally obliterated below. The flush sur-face of the inner ring resembles the same structure in Apiocrinuspolycryphus, as shown by De Loriol on plate 36, figure 4&. In com-paring the figures of De Loriol which I have copied with those of ourspecies, it must be remembered that while the former are naturalsize, the latter are one and a half times enlarged.If we had the calyx of our species greater differences might befound. In such a great distance migrational changes are likely tooccur. On the other hand, there are crinoid species of intercon-tinental distribution, for example Pentacrimis subangidavis, one ofthe best known European species, of Jurassic age, which has beenfound in Alaska, with characters so nearly identical that only varietaldifferences, if any, can be pointed out. And even among existingcrinoids, although rarely, an equal extension of range may be found,as in the case of Rhizocrinus lofotensis. which occurs from Florida toGreenland and eastward to Norway.
T Proc. U. S. Nat. Mus..v<>1. 38, 1910. p. 390. fis. ::.
EXPLANATION OF PLATEAPIOCRINUS TEHUANTEPEC, new species
SPlo. 1. Fragment of stem containing conical enlargement proximal to thecalyx, tapering for a distance of 5 columnals from 7 mm. di-ameter to 10 mm. X -?- .2 and 3. Stem fragments of larger individuals from more distal parts ofthe stem. X f.2a and 3a. Joint-faces of the -same specimens, slightly frayed at theperiphery, having about 56 striae, which extend inward forabout two-tilths of the diameter to a smooth inner ring sur-rounding the lumen. X f. Collection United States Na-tional Museum. (Jpper Jurassic, Isthmus of Tehuantepee,Mexico.APIOCRINUS ELEGANS (Defrntice)Upper Jurassic, Bathonien. Calvados, FranceFigs. 4. 4b, 4c. Joint-faces and lateral view of isolated stem fragments, show-ing t lie radiating striae, and smooth sunken inner ring. AfterDe Loriol, Pa!. France, vol. 11, pt. 1, pi. 35, figs, 4, 4b, 4c.Natural size.5.0,7. Different forms of calyx and conical stem enlargement. AfterDe Loriol, pi. 34, figs. 1, 4, 6. Natural size.PENTACRINUS SUBANGULARIS, var. ALASKA SpringerLower Jurassic. Northern AlaskaFigs. 8, 9. Two joint-faces, showing petaloid sectors with creneliae at theirmargin. Natural size. Collection United States NationalMuseum.BALANOCRINUS MEXICANUS SpringerUpper Cretaceous. Tamaulipas, MexicoFig. 10. A joint-face, showing petaloid sectors with creneliae at periphery ofthe joint. X f, Collection United States National Museum.BALANOCRINUS HAITIENSIS SpringerTertiary, Miocene. Republic of HaitiFig. 11. A joint-face, showing petaloid sectors, with shorter peripheralcreneliae. X 2. Collection United States National Museum.5o

U. S. NATIONAL MUSEUM PROCEEDINGS, VOL. 67, ART. 18 PL. I