Davila Ross, M., and Geissmann, T. (2005). Orangutan long call diversity: A phylogenetic approach. Primate Report 72-1 (Special Issue, Dec. 2005): 17-18 (Abstract only).

Orangutan long call diversity: A phylogenetic approach

Marina Davila Ross¹ and Thomas Geissmann<sup>2

1</sup> Institut für Zoologie, Stiftung Tierärztliche Hochschule Hannover, Germany,
Email: marina.davila-ross@tiho-hannover.de
² Anthropologisches Institut und Museum, Universität Zürich, Switzerland

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

The phylogenetic relationships among orangutans on Borneo and Sumatra 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 phylogenetic studies used data from wild living orangutans of exactly known provenance. Furthermore, in most studies of systematics, data from huge geographic areas (e.g. Sumatra) were pooled in the analyses, thus ignoring possibly distinct subpopulations. The present study represents a new approach to orangutan systematics, using orangutan long calls. Long calls are species-specific vocalizations produced by many nonhuman primates, and data on their acoustical structures have been used to assess relationships among, and phylogenies of, several primate taxa. We analyzed 78 long calls from wild living orangutans of five populations from Borneo and of five from Sumatra. Besides the chiefly paraphyletic topology of cladistic results, which do not conform nor reject a Borneo-Sumatra dichotomy, bootstrap values support three monophyletic groups (Northwest Borneo: 71-72%, Northeast-East Borneo: 62-75%, Ketambe: 75-79%). Shortest trees and multivariate analyses provide some support for a closer relationship among Sumatran and certain Bornean populations than among particular Bornean populations themselves, indicating that conservation management should be based on orangutans from different populations rather than on just two island-specific groups.