Geissmann, T.; Dallmann, R. & Pastorini, J. 2002: The Javan silvery gibbon (Hylobates moloch): Are there several subspecies? In: Caring for primates. Abstracts of the XIXth congress of the International Primatological Society, 4th-9th August, 2002, Beijing, China, pp. 120-121. Mammalogical Society of China, Beijing.

The Javan silvery gibbon (Hylobates moloch): Are there several subspecies?

Thomas Geissmann1, Robert Dallmann2 & Jennifer Pastorini3

1 Institute of Zoology, Tierärztliche Hochschule, Bünteweg 17, 30559 Hannover, Germany, e-mail: thomas.geissmann@gibbons.de
2 Institute of Zoology, Tierärztliche Hochschule, Bünteweg 17, 30559 Hannover, Germany, e-mail: robert@dallmanns.de
3 Anthropologisches Institut, Universität Zürich, Winterthurerstrasse 190, 8057 Zürich, Switzerland, e-mail: jenny@aim.unizh.ch


Key Words: systematics, rehabilitation program, conservation

Although Sody (1949) described Central Javan gibbons as a distinct subspecies (Hylobates lar pongoalsoni), this was not confirmed by subsequent taxonomists, and Javan gibbons (Hylobates moloch) are traditionally being regarded as monotypic. Recently, DNA sequence data from the control region of Javan zoo and pet gibbons were reported to suggest the presence of two genetically differentiated lineages representing different management units that should be managed separately (Supriatna et al. 1999; Andayani et al. 2001). As a result, it was concluded that pet animals from both areas cannot be pooled for a rehabilitation program and that genetic screening should be applied before sending any pets to such a program (Supriatna & Manullang 1999). Some authors accept this as evidence for the presence of two gibbon subspecies on Java (Supriatna & Wahyono 2000), and this view has also been adopted by the IUCN Red List.

We critically examine all available evidence relevant for the systematics of this species. Our analysis of fur coloration of the majority of museum skins from known Javan localities does not support the recognition of two distinct populations. A detailed analysis of gibbon song vocalizations recorded from all major wild populations of H. moloch weakly supports the recognition of two clades, but the boundary between them is located much more to the east than the boundary reported to exist between the molecular clades. A re-analysis of the published DNA sequences produces up to six genetically distinct clades. In addition, genetic divergences within each clade reach the range for between clade comparisons. Based on the available evidence, recognition of two subspecies is not warranted. This finding has direct implications for any programs directed at breeding and rehabilitating Javan silvery gibbons.



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