The Nullarbor dwarf bettong, ''Bettongia pusilla'', was a

potoroine Potoroidae is a family of marsupials, small Australian animals known as bettongs, potoroos, and rat-kangaroos. All are rabbit-sized, brown, jumping marsupials and resemble a large rodent or a very small wallaby. Taxonomy The potoroids are sm ...

marsupial that occurred in Australia. The animal is only known from skeletons found in caves of the

Nullarbor Plain The Nullarbor Plain ( ; Latin: feminine of , 'no', and , 'tree') is part of the area of flat, almost treeless, arid or semi-arid country of southern Australia, located on the Great Australian Bight coast with the Great Victoria Desert to its ...

and is now classified as recently extinct.

Taxonomy

The Nullarbor dwarf bettong was a species of ''

Bettongia Bettongs, species of the genus ''Bettongia'', are potoroine marsupials once common in Australia. They are important ecosystem engineers displaced during the colonisation of the continent, and are vulnerable to threatening factors such as altere ...

'', a genus that includes still living species such as the

northern bettong The northern bettong (''Bettongia tropica'') is a small, endangered, gerbil-like mammal native to forests in northeast Australia. A member of the rat-kangaroo family (Potoroidae), it moves by hopping and lives in burrows, feeding at night on root ...

, belonging to the subfamily

Potoroinae Potoroidae is a family of marsupials, small Australian animals known as bettongs, potoroos, and rat-kangaroos. All are rabbit-sized, brown, jumping marsupials and resemble a large rodent or a very small wallaby. Taxonomy The potoroids are sm ...

. The description was first published in 1997 by R. A. McNamara, using specimens collected on the Nullarbor Plain from the Koonalda and Weekes Caves. The

holotype A holotype is a single physical example (or illustration) of an organism, known to have been used when the species (or lower-ranked taxon) was formally described. It is either the single such physical example (or illustration) or one of several ...

is part of a juvenile's right jaw, with some teeth absent, obtained at the Koonalda site. The author recognised an earlier description, misidentified as ''

Caloprymnus campestris The desert rat-kangaroo (''Caloprymnus campestris''), also called the buff-nosed rat-kangaroo, plains rat-kangaroo or oolacunta,Tony Robinson & Tiana Forrest (2012A possible sighting of the Desert Rat-kangaroo or Oolacunta (''Caloprymnus campestr ...

'' by

Ernest Lundelius Ernest L. Lundelius is a vertebrate paleontologist who has conducted research in the United States and Australia. Lundelius retired as professor emeritus at the Jackson School of Geosciences of the University of Texas. He was awarded a Fulbright F ...

and William D. Turnbull in 1984, and the informal reference to an potoroid species. McNamara's paper on the new species details his diagnosis as arising independently, but gives credit for the discovery to earlier worker's identification of the taxon as 'Thomson's unnamed Potoroid' or 'Unnamed potoroid' (Baynes 1987). The epithet ''pusilla'' is derived from Latin, a reference to the small size of the animal. The English vernacular Nullarbor dwarf bettong was suggested by McNamara and is used to refer to this species.

Description

''Betongia pusilla'' show a form of dentition and jaw structure that distinguishes them from others of the genus. The mandible is lighter than the extant species, and the teeth are smaller. Molars of ''Bettongia pusilla'' are straight sided with an elevated crown, which contrasts with the bulbous shape of other ''Bettongia'' species.

Distribution and habitat

Only known from a series of skeletal remains found in caves on the

, an arid desert region of southern Australia. The species is assumed to have become extinct in the states of

Western Western may refer to: Places *Western, Nebraska, a village in the US *Western, New York, a town in the US *Western Creek, Tasmania, a locality in Australia *Western Junction, Tasmania, a locality in Australia *Western world, countries that id ...

and

South Australia South Australia (commonly abbreviated as SA) is a state in the southern central part of Australia. It covers some of the most arid parts of the country. With a total land area of , it is the fourth-largest of Australia's states and territories ...

during the period of colonisation.

References

{{Taxonbar, from=Q1827145 Bettongia Nullarbor Plain Mammals described in 1997 Fossil taxa described in 1997