Southern Common Cuscus

biology_ecology

HABITAT: Rand and Brass (1940) provide descriptions of the southern New Guinea region that contains the collecting localities for P. mimicus. In the area along the coast, south of the estuary of the Fly River (which includes the Oriomo River: fig. 1, locality 62), the predominant vegetation type is scrub savanna. Rainforest occurs chiefly as fringing strips of no more than 100 – 200 m in depth along creeks and streams, and in isolated patches on ridge tops (fig. 6). The rainforest is described by Rand and Brass as ‘‘ poor and light’ ’, with some areas that ‘‘ could only be described as dense brush’ ’. Savanna trees, including Acacia and Tristania, intrude into the rainforest. The savannas are dominated by Melaleuca; on ridges this genus mixes with Tristania, Eucaplyptus, and Acacia to form savanna forests with a thin, high canopy and a ground cover of grasses. During the rainy season the flat savannas become boggy, and can flood up to a foot (Brass and Rand, 1940). In contrast, the areas around the Palmer River Camp (fig. 1, locality 63) and the Black River Junction (fig. 1, locality 64) in the northern part of Western Province are typified by steep ridges rising up to 100 m above

Systematic Revision Within the Phalanger orientalis Complex (Diprotodontia, Phalangeridae): A Third Species of Lowland Gray Cuscus from New Guinea and Australia

description

DESCRIPTION: Critical skull dimensions are listed in table 2. The most notable feature of the skull is the shape of the zygomatic arches. In all other species of Phalanger the arches reach their widest point at the caudal end, near the suture between the jugal and the squamosal, and converge toward the midline of the skull rostrally. In P. mimicus the arches run parallel to the midline, or even diverge rostrally, giving the skull a different shape (fig. 3). In general the skull shows less development of the supraorbital, parietal, and sagittal crests than is seen in other species of the genus; indeed, it is not unusual for the parietal crests to remain unfused, even in very old individuals. The facial extent of the lachrymal is comparatively small, as in P. intercastellanus. The frontals are deeply penetrated by the nasal bones; the nasals do not taper abruptly at their caudal extremity, but are rounded (fig. 4). The teeth are remarkably small, even given the overall small size of the animals. In this respect P. mimicus is similar to the rare montane Telefomin cuscus, P. matanim (Flannery, 1987). The welldeveloped postparacrista on M 1, with its pronounced buccal kink (fig. 5), is

Systematic Revision Within the Phalanger orientalis Complex (Diprotodontia, Phalangeridae): A Third Species of Lowland Gray Cuscus from New Guinea and Australia

description

Phalanger microdon Tate and Archbold, 1935. Phalanger orientalis peninsulae Tate, 1945.

Systematic Revision Within the Phalanger orientalis Complex (Diprotodontia, Phalangeridae): A Third Species of Lowland Gray Cuscus from New Guinea and Australia

diagnosis

DIAGNOSIS: Skull and teeth small, molars especially so. Lachrymal contribution to the face is short. Zygomatic arches run parallel or diverge from midline of skull rostrally Well­developed postparacrista on M 1, with a pronounced buccal kink. Distinguished from P. orientalis and P. intercastellanus by its smaller size, lack of convergence of zygomatic arches rostrally, and by well­developed postparacrista. Distinguished from P. orientalis by absence of white tail tip in females. Distinguished from P. intercastellanus by absence of lingual cingulum on protocone of M 2.

Systematic Revision Within the Phalanger orientalis Complex (Diprotodontia, Phalangeridae): A Third Species of Lowland Gray Cuscus from New Guinea and Australia