This marsupial family includes 4 genera and 10 species of bandicoots and bilbies. One genus, Chaeropus (pig-footed bandicoot), is probably now extinct, but it was fairly widely distributed when Europeans first entered Australia. Bandicoots (genera Isoodon and Perameles) are classified together in the subfamily Peramelinae; bilbies ( Macrotis) are placed in a separate subfamily, Thylacomyinae. The pig-footed bandicoot may belong with the Peramelinae, or it perhaps should be classified by itself.
Members of the family Peramelidae range in body size from a few hundred grams to about 2 kilograms. Their hind limbs are long and adapted for hopping or running (but curiously, also maintain some traits such as an enlarged fibula that are probably related to digging). The feet are 
syndactylous and usually digitigrade, the fourth digit is large and the other digits are usually reduced. Their dental formula is 4-5/3, 1/1, 3/3, 4/4 = 46 or 48. Their molars are either tribosphenic or quadrate.
Peramelids can be distinguished from the other living family in the order Peramelemorphia (Peroryctinae) by their relatively flattened crania (vs. conical in peroryctids), and by molecular characteristics. Peramelids tend to inhabit relatively dry habitats, in contrast to peroryctids, which are usually found in rainforest.
Peramelids are unusual among marsupials in that their embryos form a placenta (seen in no other marsupials except the koala and wombats). Gestation, however, is very brief, lasting as little 12.5 days from conception to birth in some species. Peramelids have a well developed pouch.
Literature and references cited Feldhamer, G. A., L. C. Drickamer, S. H. Vessey, and J. F. Merritt. 1999. Mammalogy. Adaptation, Diversity, and Ecology. WCB McGraw-Hill, Boston. xii+563pp.
Marshall, L. G. 1984. Monotremes and marsupials. Pp 59-115 in Anderson, S. and J. Knox Jones, eds, Orders and Families of Recent Mammals of the World. John Wiley and Sons, NY. xii+686 pp.
Strahan, R. (ed.). 1995. Mammals of Australia. Smithsonian Institution Press, Washington, D.C. 756 pp.
Vaughan, T. A. 1986. Mammalogy. Third Edition. Saunders College Publishing, Fort Worth. vi+576 pp.
Vaughan, T. A., J. M. Ryan, N. J. Czaplewski. 2000. Mammalogy. Fourth Edition. Saunders College Publishing, Philadelphia. vii+565pp.
Wilson, D. E., and D. M. Reeder. 1993. Mammal Species of the World, A Taxonomic and Geographic Reference. 2nd edition. Smithsonian Institution Press, Washington. xviii+1206 pp.
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