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Peramelemorphia
Temporal range: Late Oligocene–Recent
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A short-nosed bandicoot (Isoodon spp.)
Scientific classification
Kingdom: Animalia
Phylum: Chordata
Class: Mammalia
Infraclass: Marsupialia
Order: Peramelemorphia
Ameghino, 1889
Families

Yaralidae Thylacomyidae
Chaeropodidae
Peramelidae

The order Peramelemorphia includes the bandicoots and bilbies: it equates approximately to the mainstream of marsupial omnivores. All members of the order are endemic to the twin land masses of Australia-New Guinea and most have the characteristic bandicoot shape: a plump, arch-backed body with a long, delicately tapering snout, very large upright ears, relatively long, thin legs, and a thin tail. Their size varies from about 140 grams up to 2 kilograms, but most species are about the weight of a half-grown kitten: somewhere around one kilogram.

Phylogeny

Placement within Marsupialia

The position of the Peramelemorphia within the marsupial family tree has long been puzzling and controversial. There are two morphological features in the order that appear to show a clear evolutionary link with another marsupial group: the type of foot, and the teeth. Unfortunately, these clear signposts point in opposite directions.[citation needed]

All members of the order are polyprotodont (have several pairs of lower front teeth)—in the case of the Peramelemorphia, three pairs. This suggests that they have evolved within Dasyuromorphia (marsupial carnivores). On the other hand, they also have an unusual feature in their feet: the second and third toes are fused together. This condition is called syndactyly, and is characteristic of the Diprotodontia (the order of marsupial herbivores that includes kangaroos, wombats, possums, and many others).[citation needed]

Attempts to resolve this puzzle include the view that the bandicoot group evolved from the carnivores, retaining the polyprotodont dentition, and independently evolving a syndactyl hind foot; the contrary view that syndactyly is so unusual that it is unlikely to have evolved twice and therefore the bandicoot group must have evolved from a possum-like diprotodont creature, and re-evolved its extra teeth. A third view suggests that the bandicoot group evolved from a primitive carnivore, developed the syndactylous hind foot as a specialisation for climbing, and the diprotodonts then split off and evolved the two-tooth jaw that gives them their name. Recent molecular level investigations do not so far appear to have resolved the puzzle, but do strongly suggest that whatever the relationship of the bandicoot group to the other marsupial orders may be, it is a distant one.[citation needed]

Relationships within Peramelemorphia

Recent molecular analyses have resulted in a phylogenetic reconstruction of the members of Peramelemorphia with quite strong support. The most basal split separates Thylacomyidae (Macrotis) from all other bandicoots. Probably the next to diverge was the recently extinct Chaeropodidae (Chaeropus). The remaining taxa comprise the Peramelidae, which divides into subfamilies Peramelinae (Isoodon and Perameles) and a clade in which the Echymiperinae (Echymipera and Microperoryctes) form a sister group to Peroryctinae (Peroryctes):[1]

Peramelemorphia

Thylacomyidae

Macrotis



†Chaeropodidae

Chaeropus


Peramelidae

Peramelinae


Isoodon



Perameles




Echymiperinae


Echymipera



Microperoryctes



Peroryctinae

Peroryctes






References

  1. ^ Meredith, Robert W.; Westerman, Michael; Springer, Mark S. (2008). "A timescale and phylogeny for "Bandicoots" (Peramelemorphia: Marsupialia) based on the sequences for five nuclear genes". Molecular Phylogenetics and Evolution. 47 (1): 1–20. PMID 18328736. doi:10.1016/j.ympev.2008.01.002. 

[1]Template:Peramelemorphia

Macropus eugenii 2 Gould This article is part of Project Mammal Orders, a All Birds project that aims to write comprehensive articles on each mammal order, including made-up orders.
Mammal Diversity 2011 This article is part of Project Mammal Taxonomy, a All Birds project that aims to write comprehensive articles on every order, family and other taxonomic rank related to mammals.

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