''Simosthenurus occidentalis'' is a species of

sthenurine Sthenurinae (from ''Sthenurus'', Greek for 'strong-tailed') is a subfamily within the marsupial family Macropodidae, known as 'short faced kangaroos'. No members of this subfamily are extant today, with all becoming extinct by the late Pleistocen ...

marsupial ("short-faced kangaroo") that existed in Australia during the

Pliocene The Pliocene ( ; also Pleiocene) is the epoch in the geologic time scale that extends from 5.333 million to 2.58Pleistocene The Pleistocene ( , often referred to as the '' Ice age'') is the geological epoch that lasted from about 2,580,000 to 11,700 years ago, spanning the Earth's most recent period of repeated glaciations. Before a change was finally confirmed ...

epoch around 42,000 years ago. It was a large herbivorous biped that resembles large kangaroos, but with a heavier body than modern kangaroos. The structure of the skull and teeth - resembling koalas and panda bears - indicates that it consumed tough vegetation.

Taxonomy

The type specimen was collected by E. A. Le Souef and noted in a report to the state's Caves Board, then revised and published by

Ludwig Glauert Ludwig Glauert MBE (5 May 1879 – 1 February 1963) was a British-born Australian paleontologist, herpetologist and museum curator. He is known for work on Pleistocene mammal fossils, and as a museum curator who played an important role i ...

as ''Sthenurus occidentalis'' in 1910. This holotype is fossil material preserving the left and right dentary of an adult found at

Mammoth Cave Mammoth Cave National Park is an American national park in west-central Kentucky, encompassing portions of Mammoth Cave, the longest cave system known in the world. Since the 1972 unification of Mammoth Cave with the even-longer system under F ...

Southwest Australia Southwest Australia is a biogeographic region in Western Australia. It includes the Mediterranean-climate area of southwestern Australia, which is home to a diverse and distinctive flora and fauna. The region is also known as the Southwest Aus ...

. The specific epithet ''occidentalis'', meaning "of the west", refers to the discovery of this species in Western Australia.

Description

A mid-sized species of ''

Simosthenurus ''Simosthenurus,'' also referred to as the short-faced kangaroo, is an extinct genus of megafaunal macropods that existed in Australia, specifically Tasmania, during the Pleistocene. Analysis of ''Simosthenurus'' fossils has contributed to the f ...

'', known as 'short-faced' kangaroos, one of several genera in a macropodid lineage that diversified in

Pliocene The Pliocene ( ; also Pleiocene) is the epoch in the geologic time scale that extends from 5.333 million to 2.58 The short jaw and facial anatomy clearly distinguishes their appearance from the surviving lineage of kangaroos, which usually graze on grasses rather than a browsing diet, and more closely resembles the habits of the modern koala ''

Phascolarctos cinereus The koala or, inaccurately, koala bear (''Phascolarctos cinereus''), is an arboreal herbivorous marsupial native to Australia. It is the only extant representative of the family Phascolarctidae and its closest living relatives are the womba ...

''. A set of powerful molars located close to the hinge of jaw, similar to but further back than a koala, improved the mechanical advantage and a potential enlargement of the zygomaticomandibularis muscles would have reduced the hazard of dislocation while biting with the rear molars. Modelling of the bite force and the skulls resistance to torsional forces suggests that the species was able to consume tough material, such as leaves, bark and branches, that could be torn with the claws of the long forelimbs. The diamond-like shape of the forehead and reinforced cheek bones was able to distribute the forces applied by large muscles to the rear molars at one side of the jaw, strongly suggesting that browsing habit included an ability to tear and chew hardy and fibrous material. The morphology of the skull and dentition was found to be most comparable to Asian mammal '' Ailuropoda melanoleuca'' (panda), an animal that primarily feeds as a browser of tough plant material.

Distribution and habitat

The species is represented in the records of many southern fossil sites in Australia, including Tasmania. The type locality is located in Southwest Australia, at Mammoth Cave, and evidence from another site in the southwest indicates it existed until about 42,000 years ago. Fossils assigned to the species have been obtained at sites in the Southwest, southern regions of Central Australia and the southeast of the continent. In Tasmania ''S. occidentalis'' has been identified at fossil sites in the northeast and central regions, the species has also been found at the nearby

King Island King Island, Kings Island or King's Island may refer to: Australia * King Island (Queensland) * King Island, at Wellington Point, Queensland * King Island (Tasmania) ** King Island Council, the local government area that contains the Tasmanian isl ...

. Their distribution in the Pleistocene is dated to late-middle to late deposits.

References

{{Taxonbar, from=Q25385129 Species described in 1910 Macropods Marsupials of Australia Taxa named by Ludwig Glauert