Phalanger orientalis (Pallas, 1766)

Pine, Ronald H., Mack, Andrew L. & Timm, Robert M., 2017, Marsupials And Rodents Of The Admiralty Islands, Papua New Guinea, Occasional Papers of the Museum 352, pp. 1-30 : 4

Phalanger orientalis (Pallas, 1766)

Northern Common Cuscus

It is clear that Tate (1945:13) knew of no Phalanger orientalis from the Admiralties, for he wrote: “If orientalis is represented on the Admiralty Islands and St. Matthias it may be expected to conform to this general type [like animals from ‘Long Island and Ruk,’ etc.].” Kisokau (1974), however, recorded both “ Phalanger maculata ” (presumably = Spilocuscus kraemeri ) and Phalanger orientalis from “Rambutso Island” [= Rambutyo Island] and “ Phalanger maculata ” (again, presumably = S. kraemeri ) from Lou. Menzies and Pernetta (1986) seem to be the only authors who have taken note of Kisokau’s report. They wrote that they had seen no specimens of P. orientalis from the Admiralties but that they would expect them to be of the “subspecies” P. o. intercastellanus Thomas, 1895 (now regarded as a species in its own right—see Colgan et al. 1993). One might wonder if some or all of the animals reported by Kisokau, as Phalanger orientalis , might be misidentified Spilocuscus kraemeri —young individuals and/or adult females, and/or individuals of the nearly uniformly silver gray color phase mentioned by Cohn (1914). However, as a native of Manus (see Flannery 2011), Kisokau is one to be expected to know how to tell Spilocuscus kraemeri from Phalanger orientalis , and so we are inclined to accept his having regarded the two as sympatric on Rambutyo. In this regard, Helgen and Flannery (2004), who think that Spilocuscus kraemeri may occur on New Britain , explained its rarity there, if it is found there, as possibly owing to competitive interactions with Phalanger orientalis on that island. Accordingly, Helgen and Flannery also hypothesized that the commonness of S. kraemeri on Manus could be explained by the absence of P. orientalis . However, Helgen and Jackson (2015) listed P. o. breviceps Thomas, 1888, for Manus, and assumed that it had been introduced. We know of no evidence, however, that it has ever occurred there. They did not list Rambutyo as an island occupied by this species.