Chattian extinctions

Proborhyaenidae is an extinct family of metatherian mammals of the order Sparassodonta, which lived in South America from the Eocene (Mustersan) until the Oligocene (Deseadan). Sometimes it has been included as a subfamily of their relatives, the borhyaenids (as Proborhyaeninae). The largest species, Proborhyaena gigantea, is estimated to be about the size of a spectacled bear, with its skull reaching in length, and body mass estimates up to approximately , making the proborhyaenids some of the largest known metatherians. Proborhyaenid remains have been found in western Bolivia, Uruguay, south

Dichobunidae is an extinct family of basal artiodactyl mammals from the early Eocene to late Oligocene of North America, Europe, and Asia. The Dichobunidae include some of the earliest known artiodactyls, such as Diacodexis.

Mammalodontidae is a family of extinct whales known from the Oligocene of Australia and New Zealand.

Archaeohyracidae is an extinct family of notoungulate mammals known from the Paleocene through the Oligocene of South America. First named in 1897, it is now thought to be paraphyletic, rather than a genuine group of closely related animals with a single, unique, ancestor.

The Ellimmichthyiformes, also known as double-armored herrings, are an extinct order of ray-finned fish known from the Late Jurassic to the Oligocene. They were the sister group to the extant true herrings, shad and anchovies in the order Clupeiformes, with both orders belonging to the suborder Clupeomorpha. Some studies suggest that the order may be potentially paraphyletic with respect to crown-group Clupeiformes.