Phalangerids are relatively large, compared with other possums. The smallest species, the Sulawesi dwarf cuscus, is cat-sized, averaging in length, while the largest, the black-spotted cuscus, is around long, and weighs. Besides the large size, other key features distinguishing phalangerids from other possums include the presence of bare skin on at least part of the tail, and low-crowned molar teeth. They have claws on the fore feet, but none on the hind feet, although these do have an opposable first toe to help grip onto branches. Additionally, in all but one species, both the first and second digits of the fore feet are opposable. The fur is typically dense or woolly, and may be grey, black, or reddish-brown, often with spots or stripes. Most phalangerids are folivores, feeding primarily on leaves. Like some similar species, they have a large cecum to ferment this highly fibrous food and extract as much nutrition as possible. However, their teeth are not as highly adapted to this diet as in other possums, and they also eat fruit, and even some invertebrates. The only exception to these general rules is the ground cuscus, which is carnivorous, and is also less arboreal than other phalangerid species. The dental formula of phalangerids is: Gestation in phalangerids lasts 16–17 days in those species so far studied. The females have a well-developed pouch, and typically raise only one or two young at a time, less than many other possums. The adults are typically solitary, defending territories marked by scent-gland spray, odiferous saliva, urine, or dung. Most possums conserve the functions of the epipubic bones. The exception is Trichosurus, which remarkably among marsupials has shifted the hypaxial muscles from the epipubic to the pelvis, employing a more placental-like breathing, having lost the benefits of the epipubic in regards to lung ventilation. In general, these possums are more terrestrial than other members of this group, and resemble terrestrial primates in some respects.
Classification
This classification is based on Ruedas & Morales 2005. The family Phalangeridae consists of six genera and 28 species.
reconstructs the form*kandoRa ‘cuscus’ for Proto-Central–Eastern Malayo-Polynesian, but the validity of this reconstruction is doubted by Schapper. Schapper shows that reconstructed forms for ‘cuscus’ are in fact quite diverse, and cannot be reconstructed to Proto-Central–Eastern Malayo-Polynesian. Other names for ‘cuscus’ are:
Proto-Timor: *madar
Proto-Southeast Maluku: *mander
Proto-Central Maluku: *mansər
Proto-Oceanic: *kadroRa; there was a semantic shift from ‘cuscus’ to ‘bandicoot’ from Proto-Central–Eastern Malayo-Polynesian to Proto-Oceanic for the form *mansr.