Thalmann, U., and Geissmann, T. (2000). Distribution and geographic variation in the western woolly lemur (Avahi occidentalis) with description of a new species. International Journal of Primatology 21: 915-941.

Distribution and geographic variation in the western woolly lemur (Avahi occidentalis) with a description of a new species

U. Thalmann ¹ & T. Geissmann <sup>2

1</sup> Anthropological Institute, University Zürich-Irchel, Switzerland
² Institute of Zoology, Tierärztliche Hochschule Hannover, Germany

Key words: Systematics; Avahi occidentalis; western woolly lemur; Madagascar; new species.

Abstract: The western woolly lemur is distributed through central western, northwestern and possibly northern Madagascar and is traditionally viewed as a monotypic species (Avahi occidentalis) or as a subspecies of A. laniger. We present new data on body weights of Avahi which, together with previously available body weights, provide additional evidence for recognizing eastern and western woolly lemurs as two distinct species. We then re-examine the distributions of, and chromatic variation within and between, populations of western woolly lemurs. A comparative study of wild animals and museum skins reveals that several geographically discrete morphs exist in the western Avahi, which is clearly polytypic. Marked differences between populations in fur coloration suggest that at >3 distinct taxa should be recognized. The populations differ considerably in their habitat structure. In addition, field observations suggest clear differences in population density between >2 of the populations. We describe and name one new species.