Gallirallus ernstmayri, Kirchman, Jeremy J. & Steadman, David W., 2006

Kirchman, Jeremy J. & Steadman, David W., 2006, Rails (Rallidae: Gallirallus) from prehistoric archaeological sites in Western Oceania, Zootaxa 1316, pp. 1-31 : 24-27

† Gallirallus ernstmayri , new species

Holotype. Distal humerus UF 62983 ( Figure 7 A), from Balof archaeological site, New Ireland.

Paratypes. From Balof site we refer the following specimens: Coracoids UF 63716, 63717, scapulae UF 63714, 63715, pelves UF 63712, 63713, distal tibiotarsi UF 62978, 62979, 62981, 62982, 62984, 62987, partial tibiotarsi UF 62985, 62986, and distal tarsometatarsus UF 62980. From Matenbek we refer one femoral shaft UF 62976, and two partial tibiotarsi UF 62975, 62977 ( Figure 8 A). From Panakiwuk Cave we refer one proximal humerus UF 62973. From Matenkupkum Cave we refer one tibiotarsal shaft UF 62974.

Etymology. Named in fond memory of Ernst Mayr, in recognition of his unrivaled contributions to ornithology in the Western Pacific.

Diagnosis. A large rail ( Table 6 ) the size of and perhaps closely related to Gallirallus insignis from nearby New Britain, and G. woodfordi from the Solomons, that has the following unique combination of characters. Humerus: fossa musculo brachialis narrow and ovoid as in G. i n s i g n i s, but deeper and more clearly emarginated, as in fully flightless species; condylus ventralis separated from the condylus dorsalis by a deep furrow, making the condylus ventralis more prominent in anterior and distal aspects; corpus humeri extremitas distale more rounded in cross­section with a width:depth ratio higher than in all congeners (3.1:3.8 mm in † G. ernstmayri vs. 2.5:3.6 in G. i n s i g n i s, 2.6:3.5 in G. philippensis , and 2.7:4.2 in G. woodfordi ); proximal humerus similar to that in G. woodfordi in overall size and in the shape of the crista deltopectoralis, which is deeply concave in posterior aspect in both species; depression at the proximal margin of the crista deltopectoralis visible in proximal aspect (not visible in G. woodfordi ). Tibiotarsus differs from that in all congeners in these characters: foramen interosseum proximale very short; impressio ligamentum collateralis medialis deeper and with a prominent margin on facies caudalis; furrow between the corpus tibiotarsi and crista fibularis deeper and longer; pons supratendineus bulges more cranially and more visible in medial aspect. Tarsometatarsus: distal portion of corpus tarsometatarsi wider but not deeper than in G. insignis ; groove proximal to foramen vasculare distale short; fossa metatarsi I also relatively shorter than in all other congeneric species.

Remarks. The deep, distinct fossa musculo brachialis and small relative size of the humerus of † Gallirallus ernstmayri are suggestive of reduced flight capability relative to fully volant congeners. Unfortunately, the sternum is unknown, and both the wing and leg bones are too fragmentary to permit morphometric analyses of this species’ flight ability. Gallirallus insignis from New Britain is poorly known both in nature and osteologically, but is presumed to be flightless. The islands of New Ireland and New Britain were not connected during periods of lowered sea­level in the Pleistocene. There is no extant flightless rail endemic to New Ireland today.

Figures

FIGURE 7. Humerus in species of Gallirallus known from Near Oceania in anterior aspect (upper row) and posterior aspect (lower row). A. † G. ernstmayri new species, sex unknown, UF 62983, New Ireland, Bismarck Archipelago. B. G. insignis female, AMNH 27136, New Britain, Bismarck Archipelago. C. G. philippensis male, UF 39855, Tutuila, American Samoa. D. G. rovianae male, AMNH 28014, New Georgia, Solomon Islands. E. G. w o o d f o rd i female, UF 39409, Isabel, Solomon Islands. Scale = 40 mm.

FIGURE 8. Distal tibiotarsus in species of Gallirallus from Near Oceania in anterior (upper) and posterior (lower) aspects. A. † G. e r ns tm a y ri new species, sex unknown, UF 62977, New Ireland, Bismarck Archipelago. B. G. insignis female, AMNH 27136, New Britain, Bismarck Archipelago. C. G. philippensis male, UF 39855, Tutuila, American Samoa. D. G. rovianae male, AMNH 28014, New Georgia, Solomon Islands. E. G. w o od fo rd i female, UF 39409, Isabel, Solomon Islands. Scale = 20 mm.