A taxonomic revision of cuscuses allied to Phalanger orientalis (Marsupialia: Phalangeridae)

A computer-assisted discriminant analysis programme using a set of metric skull characters in a large number of specimens of cuscuses of the Phulnnger orientalis group was used to distinguish between species and subspecies. Non-metric characters were used to support conclusions.
Results indicated that several taxa which had customarily been included in the widespread species orientalis were not closely related to that species. The programme also identified the components of the long-haired mountain cuscus group and we show that the holotype of one species, vestitus , appears to be unrelated to the widespread species with which it has been associated since Tate's revision of 1945. Finally we were able to demonstrate the presence of 10 distinct species in the orientalis group (of which one is described as new) and 12 subspecies (of which three are described as new).
The same suite of metric and non-metric characters allowed construction of dendrograms indicating possible relationships between the various sub-groups and their component species. We speculate on the evolution of this group of cuscuses in New Guinea and their spread to other islands in the region.
We recount what is known about cuscus biology and provide means for identification.