Cranial description and genetic identity of the holotype specimen of Tursiops aduncus (Ehrenberg, 1832)

Two species of bottlenose dolphins are currently recognized by most cetologists: the pan-tropical and temperate Tursiops truncatus and the endemic Indo-Pacific T aduncus. The latter was described from a specimen from the Red Sea, with nothing in the description that would allow referral of the specimen to one or the other of the two species. Because both species occur in the northern Indian Ocean, it was possible that the holotype specimen was actually a common bottlenose dolphin, not of the Indo-Pacific species. The holotype skull was thought lost but has been found in the Berlin Museum. We describe the skull and examine its affinities through comparison of a partial mtDNA control-region sequence with sequences from South Africa and through application of classification functions from a discriminant analysis of the two putative species from Taiwan. The mtDNA sequence is identical to that of South African specimens referred to the Indo-Pacific species, and the multivariate likelihood assignment associates the skull with Taiwanese specimens referred to that species. These results ensure the correctness of use of the name T aduncus for the species.