Thylacoleo ("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 . Taxonomy 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, during the Late Pleistocene Epoch. Three species are known: Thylacoleo carnifex The holotype cranium was collected from Lake Colongulac in 1843 by pastoralist William Adeney. A partial rostrum collected by Adeney in 1876 from the same locality would later be found to belong to the same individual. Thylacoleo crassidentatus lived during the Pliocene, around 5 million years ago, and was about the size of a large dog. Its fossils have been found in southeastern Queensland. Thylacoleo hilli lived during the Pliocene and was half the size of T. crassidentatus. It is the oldest member of the genus. Fossils of other representatives of Thylacoleonidae, such as Microleo and Wakaleo, date back to the Late Oligocene Epoch, some 24 million years ago. 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. Material found amidst the fauna at Bow River in New South Wales, dated to the early Pliocene, was also