Pteropus coxi, Helgen & Helgen & Wilson, 2009

Helgen, Kristofer M., Helgen, Lauren E. & Wilson, Don E., 2009, Pacific Flying Foxes (Mammalia: Chiroptera): Two New Species of Pteropus from Samoa, Probably Extinct, American Museum Novitates 3646, pp. 1-40 : 14-16

Pteropus coxi , new species

HOLOTYPE: The holotype of Pteropus coxi is USNM 3791 , skull of an adult, probably male, from the ‘‘ Samoan Is. ’’, collected during the U.S. Exploring Expedition of 1838–1842. The skin of this specimen bore the number 3953 but is now apparently lost (L.K. Gordon, in litt.).

PARATYPE: USNM 3790 , skull of an adult, probably female, from ‘‘ Samoan Is. ’’, also collected during the U.S. Exploring Expedition. The skin of this specimen bore the number

3952 but, like the holotype skin, is now apparently lost (L.K. Gordon, in litt.).

DIAGNOSIS: Pteropus coxi is a large flying fox similar in cranial conformation to P. samoensis and P. anetianus — with a robust skull featuring a rostrum of moderate length, a mandible with heavily developed posterior processes, and large molars—but considerably larger than P. samoensis and P. anetianus in cranial size, with larger canines and cheekteeth ( figs. 4–6 , 8 , 10 , 14 ). Apart from P. tuberculatus of the Santa Cruz Islands (an outlying island group between the Solomon archipelago and Vanuatu), P. coxi is the only species in the genus in which the very large upper canines sometimes (in the case of P. coxi , in one of the two available specimens) bear a secondary, posterior cusp.

DISTRIBUTION: The U.S. Exploring Expedition visited the Samoan archipelago from 7 October to 10 November in 1839, exploring the islands of Tutuila, Upolu, Savai9i, and the Manua group; some members of the expedition also returned to Upolu for visits in following years (one ship, the Porpoise returned 4-8 September 1840 to Upolu; two ships, the Peacock and Flying Fish, returned 6 February to 6 March 1841; M. Grunes, in litt.). Pteropus coxi is known only by the holotype and paratype, which were collected at some time during the U.S. Exploring Expedition, but localized only generally to the ‘‘Samoan Is.[lands]’’ or ‘‘Samoan Isle’’ on their accompanying labels. We regard P. coxi as a Samoan endemic, although the precise insular extent of its historical distribution

TABLE 4 Specimens of Pteropus from Samoa at USNM Collected during the U.S. Exploring Expedition (all of which apparently comprise the original hypodigm or syntype series of Pteropus samoensis )

Pteropus samoensis Peale, 1858

USNM 3788/3949 ‘‘Samoan Archipelago’’, adult, skin (3949) and skull (3788)

USNM 3789 ‘‘Samoan Arch.’’, adult female, skull, accompanying skin (USNM 3950) missing

USNM 3947 ‘‘Samoan Archip.’’, adult, skin

USNM 4465 ‘‘Samoan Ids’’, adult, skull

USNM 22562 Tutuila Island, adult, skull, accompanying skin (8594) missing

USNM 37860 /8597 Tutuila Island , adult, skin (8597) and skull (37860). Lectotype of Pteropus samoensis Peale, 1858 ,designated herein (see figs. 12 , 13 )

USNM 37861/8593 Olusinga (Olosega) Island, adult male, skin (8593) and skull (37861)

USNM 37862/8596 Tutuila Island, adult female, skin (8596) and skull (37862)

USNM 37878/8595 Upolu Island, adult, skin (8595) and skull (37878)

Figures

Fig. 4. Bivariate ecomorphological contrasts in Samoan Pteropus. A plot of rostral (orbitonasal) length versus zygomatic width discriminates the four Pteropus species recorded from Samoa. Sample represents all adult specimens (or nearly adult in the case of the unique holotype of P. allenorum) from the Samoan archipelago. Open triangles indicate P. samoensis; closed diamonds, P. tonganus; closed square, P. allenorum; open circles, P. coxi.

Fig. 5. Bivariate ecomorphological contrasts in Samoan Pteropus (continued). A plot of maxillary toothrow length versus the distance across the upper canines also discriminates the four Pteropus species recorded from Samoa. Sample and symbols as for figure 4.

Fig. 6. Maxillary toothrows of the four Pteropus species of Samoa, to scale. A, Pteropus allenorum (ANSP 1234, unsexed subadult); B, Pteropus samoensis (ANSP 1867, unsexed adult); C, Pteropus coxi (USNM 3791, adult, probably male); D, Pteropus tonganus (AMNH 68738, adult male). Scale bar 5 5 mm.

Fig. 8. Multivariate morphometric comparisons in Samoan Pteropus (principal components analysis), drawing from 10 log-transformed craniodental measurements, divide the four Pteropus species recorded from Samoa into four discrete quadrant clusters. Sample and symbols as for figure 4. In this case, overall size can be visualized on the first component (increasing from right to left), while the loadings on the second component serve as an indication of general ‘‘robustness’’ (increasing from top to bottom). See text and table 3. Parenthetical numbers on the axes indicate the proportion of variance for each principal component (see table 3).

Fig. 10. Skulls of the four larger Pteropus species of Vanuatu and Polynesia. A, P. tonganus (AMNH 68738, adult male, ‘‘Samoa’’); B, P. samoensis (USNM 4465, unsexed adult, ‘‘Samoan Archipelago’’); C, P. coxi (USNM 3953/3791, probably male, ‘‘Samoan Archipelago’’); D, P. anetianus (USNM 278062, adult female, Espiritu Santo, Vanuatu). Scale bar 5 10 mm.

Fig. 14. Bivariate plot of the two canonical variates in a discriminant function analysis contrasting samples identified as Pteropus samoensis (Fiji and Samoa, triangles), Pteropus anetianus (Vanuatu, closed circles), and Pteropus coxi (Samoa, open circles). Parenthetical numbers on the axes indicate the proportion of variance for each variate (see table 5).

Fig.12. Skull of USNM 8597/37860, lectotype of Pteropus samoensis Peale, 1848. Scale bar 5 10 mm.

Fig. 13. Skin of USNM 8597/37860, lectotype of Pteropus samoensis Peale, 1848. A, dorsal view. B, ventral view.