Thylacoleo

***hylacoleo*** ("pouch lion") is an extinct genus of carnivorous marsupials that lived in Australia from the late Pliocene to the late Pleistocene (2 million to 46 thousand years ago). Some of these **marsupial lions** were the largest mammalian predators in Australia of their time, with *Thylacoleo carnifex* approaching the weight of a lioness. The estimated average weight for the species ranges from 101 to 130 kg (223 to 287 lb).[1]

The genus was first published in 1859, erected to describe the type species *Thylacoleo carnifex*. The new taxon was established in examination of fossil specimens provided to Richard Owen. The familial alliance takes its name from this description, the so-called marsupial lions of Thylacoleonidae.

The colloquial name "marsupial lion" alludes to the superficial resemblance to the placental lion and its ecological niche as a large predator. *Thylacoleo* is not closely related to the modern lion (*Panthera leo*).

**Genus:** *Thylacoleo* (*Thylacopardus*) – Australia's marsupial lions, that lived from about 2 million years ago, during the Late Pliocene Epoch and became extinct about 30,000 years ago[*citation needed*], during the Late Pleistocene Epoch.

Fossils of other representatives of Thylacoleonidae, such as *Microleo* and *Wakaleo*, date back to the Late Oligocene Epoch, some 24 million years ago.[6]

*T. hilli* was described by Neville Pledge in a study published in the records of the South Australia Museum in 1977. The holotype is a third premolar, discovered at a cave in Curramulka in South Australia, exhibiting the carnivorous characteristics of the genus and around half the size of *T. carnifex*. This tooth was collected by Alan Hill, a speleologist and founding member of the Cave Exploration Group of South Australia, while examining a site known as the "Town Cave" in 1956; the specific epithet *hilli* honours the collector of the first specimen.[5] Material found amidst the fauna at Bow River in New South Wales, dated to the early Pliocene, was also referred to the species in 1982. [7] A fragment of an incisor, unworn and only diagnosable to the genus, was located at a site in Curramulka, close to the Town Cave site, and referred to the species for the apparent correlation in size when compared to the better known *T. carnifex*.[8]

The marsupial lion is classified in the order Diprotodontia along with many other well-known marsupials such as kangaroos, possums, and the koala. It is further classified in its own family, the Thylacoleonidae, of which three genera and 11 species are recognised, all extinct. The term marsupial lion (lower case) is often applied to other members of this family. Distinct possum-like characteristics led *Thylacoleo* to be regarded as members of Phalangeroidea for a few decades. Though a few authors continued to hint at phalangeroid affinities for thylacoleonids as recently as the 1990s, cranial and other characters have generally led to their inclusion within vombatiformes, and as stem-members of the wombat lineage.[9] Marsupial lions and other ecologically and morphologically diverse vombatiforms were once represented by over 60 species of carnivorous, herbivorous, terrestrial and arboreal forms ranging in size from 3 kg to 2.5 tonnes. Only two families represented by four herbivorous species (koalas and three species of wombat) have survived into modern times and are considered the marsupial lion's closest living relatives.[10]