The koala, sometimes called the koala bear, 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 wombats. The koala is found in coastal areas of the mainland's eastern and southern regions, inhabiting Queensland, New South Wales, Victoria, and South Australia. It is easily recognisable by its stout, tailless body and large head with round, fluffy ears and large, dark nose. The koala has a body length of 60–85 cm (24–33 in) and weighs 4–15 kg (9–33 lb). Fur colour ranges from silver grey to chocolate brown. Koalas from the northern populations are typically smaller and lighter in colour than their counterparts further south. These populations possibly are separate subspecies, but this is disputed.
Diprotodontia is the largest extant order of marsupials, with about 155 species, including the kangaroos, wallabies, possums, koala, wombats, and many others. Extinct diprotodonts include the hippopotamus-sized Diprotodon, and Thylacoleo, the so-called "marsupial lion".
Bandicoots are a group of more than 20 species of small to medium-sized, terrestrial, largely nocturnal marsupial omnivores in the order Peramelemorphia. They are endemic to the Australia–New Guinea region, including the Bismarck Archipelago to the east and Seram and Halmahera to the west.
The Phascolarctidae is a family of marsupials of the order Diprotodontia, consisting of only one extant species, the koala, and six well-known fossil species, with another six less well known fossil species, and two fossil species of the genus Koobor, whose taxonomy is debatable but are placed in this group. The closest relatives of the Phascolarctidae are the wombats, which comprise the family Vombatidae.
The Vombatiformes are one of the three suborders of the large marsupial order Diprotodontia. Seven of the nine known families within this suborder are extinct; only the families Phascolarctidae, with the koala, and Vombatidae, with three extant species of wombat, survive.
Australidelphia is the superorder that contains roughly three-quarters of all marsupials, including all those native to Australasia and a single species — the monito del monte — from South America. All other American marsupials are members of the Ameridelphia. Analysis of retrotransposon insertion sites in the nuclear DNA of a variety of marsupials has shown that the South American monito del monte's lineage is the most basal of the superorder.
Phascolarctos is a genus of marsupials with one extant species, the koala Phascolarctos cinereus, an iconic animal of Australia. Several extinct species of the genus are known from fossil material, these were also large tree dwellers that browsed on Eucalyptus leaves.
The giant koala is an extinct arboreal marsupial which existed in Australia during the Pleistocene epoch. Phascolarctos stirtoni was about one-third larger than the contemporary koala, P. cinereus, and has an estimated weight of 13 kg (29 lb), which is the same weight as a large contemporary male koala.
Perameles is a genus of marsupials of the order Peramelemorphia. They are referred to as long-nosed bandicoots or barred bandicoots.
Thylacoleonidae is a family of extinct carnivorous diprotodontian marsupials from Australia, referred to as marsupial lions. The best known is Thylacoleo carnifex, also called the marsupial lion. The clade ranged from the Late Oligocene to the Late Pleistocene, with some species the size of a possum, while members of Thylacoleo reached sizes comparable to living big cats.
Wakaleo is an extinct genus of medium-sized thylacoleonids that lived in Australia in the Late Oligocene and Miocene Epochs. Although much smaller than its close relative, the marsupial lion, Wakaleo would have been a successful hunter. It had teeth specially designed for cutting and stabbing. The genus is from an extinct family of Vombatiformes, so it is distantly related to the herbivorous wombats.
Nimbadon is an extinct genus of marsupial, that lived from the Late Oligocene to the Miocene epoches. Many fossils have been found in the Riversleigh World Heritage property in north-western Queensland. It is thought to have an arboreal lifestyle.
The Riversleigh rainforest koala is an extinct marsupial, closely related to the extant koala, that inhabited northwestern Queensland in the early-middle Miocene. It is the only species assigned to the genus Nimiokoala. Along with species of sister genus Litokoala, the Riversleigh rainforest koala is the smallest representative of family Phascolarctidae. Based on cladistic analysis, Nimiokoala is one of the more basal genera of Phascolarctide. It died out due to climate change rendering the environment more arid. It probably had a more generalized diet than that of the modern species, but its exact food preferences are unknown.
Warendja is an extinct genus of wombat. It is known from two species, W. encorensis from the Late Miocene Riversleigh site in Queensland, and W. wakefieldi known from the Pleistocene of South Australia, New South Wales, and Victoria. The two species are primarily distinguished by features of their enamel. It became extinct as part of the Quaternary extinction event. Warendja wakefieldi is estimated to have weighed about 10 kg, considerably smaller than living wombats. Warendja thought to be relatively basal amongst wombats, being the most primitive member to possess hypselodont cheek teeth. The morphology of the humerus of W. wakefieldi suggests that it engaged in scratch-digging.
Litokoala is an extinct genus of marsupials, and along with Nimiokoala, is closely related to the modern koala. The three genera may have diverged at an earlier date, although the drying of the continent and the expansion of Eucalyptus forests towards the late Miocene may have delayed the evolution of cranial features unique to the modern genera. This indicates that either fossil genus could be an ancestor of the modern genus, or the modern genus has a common ancestor to both. More material needs collection to improve their taxonomical relationships.
Priscakoala is an extinct genus of koala from the Early Miocene of Riversleigh, Australia. It has one species: Priscakoala lucyturnbullae.
Perikoala is an extinct genus of marsupials, related to the modern koala. The genus diverged from a common ancestor of the other koala genera Nimiokoala, Litokoala, and Phascolarctos, which contains the living koala.
Ngapakaldia is an extinct genus of diprotodontid marsupials, related to the modern koala and wombat. Around the size of a sheep, it was a ground-dwelling herbivore that lived around the vegetated shores of lakes in Central Australia during the Late Oligocene.
Durikainema is a genus of two nematodes in the family Robertdollfusiidae. Species have a head with a cuticular cephalic inflation, elongated papillae and amphids, and well-developed musculature. Characteristics of the males include a single spicule and a long attenuated tail. Durikainema species parasitize macropods. The genus was circumscribed in 1982 with the type species Durikainema macropi, a parasite of the eastern grey kangaroo. D. phascolarcti, parasite of the koala, was described in 1998.
Koobor is an extinct genus of extinct phascolarctid marsupials. The genus contains two species: Koobor jimbarratti and Koobor notabillis.
