THE SOUTH PACIFIC GALUNULES OF THE GENUS PAREUDIASTES STORHS L. OLSON Made ill United Strties of America Kt'printrd ?i?iii 'IiiF. Wii-soN BULLETIN VlJ. K7, Nn. 1, Marcili I^IS ?>??. 1-5 THE SOUTH PACIFIC GALLINULES OF THE GENUS PAREUD?ASTES STORRS L. OLSON On 4 December 1929, a native boy on the island of San Cristobal in the Solomons carried a strange and totally unknown gallinule into the camp o? a party from the Whitney South Sea Expedition consisting of Ernst Mayr, W. F. Coultas, and W. J. Eyerdam. The sight of this specimen "gave Mayr such a thrill he nearly fainted with excitement, . . had to lay off work for the rest of the day; the thrill was too much for his constitution, which otherwise is quite sound" (Coultas and Eyerdam, in Greenway 1973:150). Some appreciation of Mayr's understandable rapture may be gained from the frontispiece which is taken from a painting done some years ago by the late F. L. Jaques and which reposed thereafter in the American Museum of Natural History. To my knowledge this is the first illustration ever published of the bird Mayr was later to name Edithornis silvestris (Mayr 193S). TAXONOMY In his original description, Mayr (1933) noticed a similarity between Edithornis dlveslris and the now extinct Pareudiastes pacijicus of Samoa. Later {Mayr 1949:22), he remarked that "a revision of the family Rallidae may reveal the necessity for combining \Edithornis\ with Pareudiastes" Green- way (1973) also believed that this would quite probably be done. In my clas- sification of the Kallidae (Olson 1973b), 1 look this step, but limitations of space prevented me from presenting many details at that time. I will take the present opportunity to offer a more complete characterization of the expanded genus Pareudiastes. While Pareudiastes silvestris can scarcely be confused with any other rail, P. pacificas bears a superficial resemblance to Gallinula. In the follow- ing diagnosis, therefore, ? have listed those characters that link the two species of Pareudiastes but which at the same time distinguish them from Gallinula. The gallinule Pareudiasles {"Edithornis"\ silvestris IMayr). From o painting by F. L. Jaques in the American Museum of Natural Fiistory. 2 THE WILSON BULLETIN ? Vol. 87, No. 1, March 1975 GENUS PAREUDIASTES IIARTLAUB AND FINSCII 1871 Included species: P. pacificus Hartlaub and Finsch (the type) ; P. silvestris (Mayr). Diagnosis: Frontal sliiftld Hatter and thinner than in Gall?nula, starting as a thin ridge above each no.etril and produced into a small but distinct Hange over the lorcal area. Posterior border of shield truncate rather than rounded as in Gall?nula. Bony nostril smaller and more rounded. Supraloreal, supraorbital, and postorbilal areas with sparse, short feathers (appearing bare), differing from the uniformly feathered face of GaUinidxi. Tarsi and toes shorter and stouter than in Gallinula. Tail much shorter, the rectrices decomposed, the undertaii coverts dark rather than white as in Gallinula (however, the undertai? coverts are dark in the subgenus Tribonyx of Gall?nula). White flank spots (characteristic of Gallinula, except most G. tenebrosa hut see Cox [1973]) lacking. lireast with a decidedly bluish tinge. I believe these characters are sufficient to separate Pareudiastes from Gallinula and to unite pacificus and silvestris in one genus. P. silvestris differs from P. pacijicas in the following characters: larger size (e.g. tarsus 63.5 mm vs. 46.9 and 40.4 in two speci- mens of pacificus) ; bill larger and heavier; gonys with two longitudinal grooves (lacking in pacificus) ; frontal shield much ?arger, extending well past the eye (in pacificus the shield reaches only to the middle of the eye) ; bare area beneath the eye more extensive; bristiy loreal feathers shorter, exposing more of the skin beneath; bluish tinge of breast more pronounced, extending also to the nape and mantle (in pacificus the dorsum is uniform dark brown). (In the rather poorly executed color plate of P. pacificas in Rothschild (1907), the bird is made to look much more bluish and Porp/iyrio-like than is true of the two specimens that I examined, while the plate in Hartlaub and Finsch (1871), although drawn much better, seems not bluish enough.) The differences between P. pacificus and P. silvestris are probably no more than would be expected between two well-isolated species of the same genus. I have been able to extract the distal end of the tarsometatarsus from a damaged specimen of P. pacificus. This proves to be quite distinct from that o? Gallinula (Fig. 1). In Pareudiastes the shaft is relatively narrower, the distal end more expanded, the inner and outer trochleae placed farther distally, the inner trochlea is not rotated as far pos- teriorly, the scar for the hallux is deeper, and all three trochleae are broader and less elongate. From that of Porphyrio (inch Porphyrula), the tarsometatarsus of Pareudiastes differs in the slightly heavier shaft, smaller distal foramen, less developed wing of the outer trochlea, more massive inner trochlea, and less sculpted and complex scar for the hallux. The tarsometatarsus of Pareudiastes can be considered as being almost perfectly interme- diate between that of Gallinula, which is typical of most rails, and that of Porphyrio, which is highly specialized for walking on floating vegetation (Olson 1973a). The more bluish coloration and the smaller, more rounded bony nostril are also characters in which Pareudiastes resembles Porphyrio. The genus Pareudiastes might therefore be regarded as a relict group occupying a position that is morphologically and perhaps pbylogenetically intermediate between Gallinula and Porphyrio. NATURAL HISTORY Very little is recorded about either species of Pareudiastes in life. Appar- ently all that is known of P. pacificus is contained in the accounts of Whitmee (1874) and Pritchard (1866). The available specimens come from the Samoan island of Savaii, but Whitmee indicates that the species also occurred Ohon . SOUTH PACIFIC CALLINULES FIO. 1. GallinulelarsometatarKi, posterior Yiew of distal end: (a) Gallinula chloropus, (b) Parcudiastef. pacificiis, (c) Porpkyno martinica. on Upolu. Armstrong (1932) states that P. pacificm was once found on Tutuila and on Tau in the Manua group, but since much in Armstrong's book appears to be unreliable, these records may be doubted. The bird inhabited montane forest. Both Pritchard (1866) and Whitmee 11874) give puna'e (meaning "springer-up" according to Pritchard) as the native name of P. pacificus, and both state that the natives consistently maintained that the birds lived in burrows in the ground. Mayr (1945) and Greenway (1958) suggested that these statements were the result of confusion between the rail and some procellariiform. That this may not have been the case, however, is evidenced by Pritchard (1866:164.). Although he never saw the bird himself, he relates that, according to the natives, the puna'e, when started from its burrow, "makes a long spring upwards from the ground, but having very small wings it cannot fly." This suggests that the bird was something other than a petrel. On the other hand, Whitmee (1874: 1!!5) reports that a punae with two eggs was taken by a native from a nest on the ground "composed of a few twigs and a little grass," a description that does not correspond with the bird's reputed burrowing habits. These eggs were described as being "of much less breadth, longer, and lighter in colour" than those of the indigenous Porphyrio. Hardaub and Finsch (1871) remarked on the large eyes of P. pacificus, from which Greenway (1958) inferred that the species might have been crepuscular or nocturnal. Wbitmee and Pritchard both indicate that the diet of P. pacijicus consisted almost entirely of animal matter and Whitmee told of captive birds that fared poorly when fed on a vegetable diet. 4 THE WILSON BULLETIN ? Vol. 87, No. 1, March 1975 While the natives esteemed the puna'e as food, ils apparent demise is probably attributable to rats, cats, and other introduced predators. There are no authenticated records of P. pacificas after 1873; the Whitney Ex- pedition failed to find it in 1926 (Greenway 1958). It has since then been presumed extinct. Of P. silvestTis even less is known. The type and only specimen was taken m montane forest at about 600 m in the center of San Cristobal in the Solomons. Mayr (1933) reckoned it was truly a bird of the forest and that It was quite rare. The bird is called kia by the natives and it is hunted with dogs; presumably it has little or no flying ability. Unfortunately, the body skeleton of the type was not saved, as this would certainly have indicated to what extent the pectoral apparatus may be reduced. Galbraith and Galbrai?h (1962:22) commented that in 1953 the species was still "well-known to the natives, and apparently not rare below Nagasi," yet they failed to obtain any specimens. This rail is probably in little danger of extinction since the very steep, dense mountain forest it inhabits is virtually inaccessible and the human population of the island appears to be abandoning the mountain settlements in favor of the lowlands. ACKNOWLEDGMENTS I am very much indebted to Dean Amadon and the American Museum of Natural History, both for permission to reproduce the painting by F. L. Jaques that forms the frontispiece, and for access to specimens of PareudiasUs. For reading and commenting on the manuscript I am also grateful to John Farrand, Jr., Kenneth C. Parkes, and Dean Amadon. LITERATURE CITED ARMSTRONG, J. S. 1932. Hand-list to the birds of Samoa. Jchn Bale, Sons & Daiiielsson, London. Cox, J. t?. 1973. Are the Dusky and Common Moorhen one species? S. Aust Ornithol 26:66. CALiiRAiTi,, I. C. J. AND E. H. GA,.i,HAiT[i. 1962. Land birds of Guadalcanal and the San Cristcval group, eastern Solomon Islands. Bull. Br. Mus. (Nat. Hist.), Zool. GKEENWAY, J. C, JK. 1958. Extinct and vanishing birds of the world. Spec. Publ. No. 13, Araer. Comm. Int. Wild Life Protection, N.Y. . 197,3. Type specimens of birds in the American Museum of Natural History. Part 1. Buli. Am. Mus. Nat. Hist. 150:207-345. HARTLAUE, G. AND 0. FiNSCH. 1871. On a collection of birds from Savai and Rarotonga Islands in the Pacific. Proe. Zool. Soc. Lond. 1871:21-32. MAYR, E. 1933. Birds collected during the Whitney South Sea Expedition. XXII. Three new genera from Polynesia and Melanesia. Am. Mus. Novit. No. 590. ? 1945. Birds of the southwest Pacific. Macmillan, N.Y. . 1949. Notes on tlie birds of northern Melanesia. 2. Am. Mus. Novit. No. 1417. Olson ? SOUTH PACIFIC GALLINULES 5 0,.so?, S. L. 1973a. Evolution of the rails of the South Atlartfc Islands (Aves: Rallidae). Smithson.Contrib.Zoo1. l&2:l-53. ?^-^31-416 1973b A clas?fication of the Rallidae. Wilson Bull. 85-d?i *"'? . P.^;.i W T. 1866. Polynesian .en.ini.cences; o. Uf. in the South Pacfte t.lands. Ro...Sr::;^'lSi' OnSnct and vanisKin, bi.ds. Ptoe. .th Int. O.nithol. Con... WH?:"s.\'?''lS:'?Lettc. on Di?uncaUs and Pareuaia.es in Sa.oa.l Proc. Zool. Soc. Lond. 1874:183-18fi. ^..vrIO.NAL MUSEUM OF NATURAL HISTORY, SMITHSONIAN INSTITUTION, WASHING- TON, DC 20560. ACCEPTED 24 .JULY 1974.