Oligocene mammals of Australia

Obdurodon is a genus of extinct platypus-like Australian monotreme which lived from the Late Oligocene to the Late Miocene. Three species have been described in the genus, the type species Obdurodon insignis, plus Obdurodon dicksoni and Obdurodon tharalkooschild. Obdurodon appeared much like their modern day relative the platypus, except adults retained their molar teeth, and unlike the platypus, which forages on the lakebed, they may have foraged in the water column or surface.

Ekaltadeta is an extinct genus of marsupials related to the modern musky rat-kangaroos. Ekaltadeta was present in what is today the Riversleigh formations in Northern Queensland from the Late Oligocene to the Miocene, and the genus includes three species. The genus is hypothesized to have been either exclusively carnivorous, or omnivorous with a fondness for meat, based on the chewing teeth found in fossils. This conclusion is based mainly on the size and shape of a large buzz-saw-shaped cheek-tooth, the adult third premolar, which is common to all Ekaltadeta.

Janjucetus is an extinct genus of baleen whale that lived during the Late Oligocene (Chattian) in south-east Australia, around 25 million years ago. Remains of the genus have been found in the Jan Juc Marl in the Jan Juc Formation near the township of the same name, and have been assigned to two species: the type species J. hunderi and J. dullardi. This locality has yielded remains of more extinct cetaceans, including Prosqualodon, Waipatia, and the related Mammalodon.

Wakaleo (Diyari waka, "little", "small"; and Latin leo, "lion") is an extinct genus of medium-sized thylacoleonids that lived in Australia in the Late Oligocene and Miocene Epochs.

Yalkaparidon is an extinct genus of Australian marsupials, first described in 1988 and known only from the Oligo-Miocene deposits of Riversleigh, northwestern Queensland, Australia.

Prosqualodon is an extinct genus of Early to Middle Miocene cetacean from Argentina, Australia, New Zealand, and Venezuela.

thumb|Life restoration Nimbacinus is an extinct genus of thylacinid contains two species of carnivorous, quadrupedal marsupials in Australia both of which are extinct: Nimbacinus dicksoni Muirhead & Archer, 1990 Nimbacinus peterbridgei Churchill, Archer & Hand, 2024

Badjcinus is an extinct thylacinid marsupial. It is the earliest and most primitive known thylacinid, living 23 to 28 million years ago in the late Oligocene.

Yarala is a genus of fossil mammals that resemble contemporary bandicoots. The superfamily Yaraloidea and family Yaralidae were created following the discovery of the type species Yarala burchfieldi in 1995, on the basis that it lacks synapomorphies that unite all other peramelemorphian taxa.

Ilaria is an extinct genus of marsupial of the family Ilariidae, dating from the Late Oligocene of South Australia. Its diet consisted of leaves.

Lekaneleo is a fossil genus of carnivorous marsupial that existed during the early Miocene in Australia. Once allied to the type species of the genus Priscileo, later placed as Wakaleo pitikantensis, "Priscileo" roskellyae was subsequently transferred to its own genus Lekaneleo.

Nambaroo is an extinct genus of macropod marsupial from the late Oligocene to the early Miocene of Australia.

Galadi is an extinct genus of predatory bandicoot from Oligo-Miocene deposits of Riversleigh, northwestern Queensland, Australia. It was first named by K.J. Travouillon, Y. Gurovich, R.M.D. Beck and J. Muirhead in 2010 and the type species is Galadi speciosus; additional three species, G. adversus, G. amplus and G. grandis, were described in 2013. The genus is represented by three well-preserved skulls and several isolated maxillae and dentaries. Its body mass would have been close to two pounds, making it relatively large for its family. The combination of body size, robustness

species of mammal (fossil)

Willungacetus is an extinct genus of primitive baleen whale of the family Aetiocetidae known from the Oligocene of Australia (at Port Willunga, , paleocoordinates ). It is the oldest-known whale from Australia, and the only aetiocetid whale currently known from the Southern Hemisphere.