Davila Ross, M., and Geissmann, T. (2006). Call diversity of wild male orangutans: A phylogenetic approach. American Journal of Primatology (in press).

Call diversity of wild male orangutans: A phylogenetic approach

Marina Davila Ross¹ and Thomas Geissmann²

¹ Institute of Zoology, University of Veterinary Medicine Hannover, D-30559 Hannover, Germany
² Institute of Anatomy, Zürich University, CH-8057 Zürich, Switzerland

Key Words: orangutans (Pongo spp.), long call, call diversity, phylogeny, population differences, conservation.

Abstract: The systematic and phylogenetic relationships among orangutan taxa are controversial, although - over the past twenty years - several studies have attempted to clarify orangutan systematics based on DNA sequences and karyological and morphological data. Surprisingly, few systematic studies have used data from wild living orangutans of exactly known provenance. Furthermore, in most studies, data from huge geographic areas were pooled in the analyses, thus ignoring possibly distinct subpopulations. This study represents a new approach to orangutan systematics which uses orangutan long calls. Long calls are species-specific vocalizations of many nonhuman primates, and data on their acoustical and temporal structures have been used to assess relationships among, and phylogenies of, several primate taxa. Altogether, 78 long calls from wild living orangutans of five populations from Borneo and of five from Sumatra were included in the analyses. Besides the chiefly paraphyletic topology of cladistic results, which neither support nor reject a Borneo-Sumatra dichotomy, bootstrap values support three monophyletic clades (Northwest Borneo, Northeast-East Borneo, Ketambe) that corroborate geographic groups. Shortest trees and multivariate analyses provide some support for a closer relationship between Sumatran and specific Bornean demes than between particular Bornean demes themselves, indicating that conservation management should be based on orangutans from different populations rather than on just the two island-specific groups.