Astrapotheria

Astrapotheria is an extinct order of South American and Antarctic hoofed mammals that existed from the late Paleocene to the Middle Miocene, . Astrapotheres were large, rhinoceros-like animals and have been called one of the most bizarre orders of mammals with an enigmatic evolutionary history.

Trigonostylops is an extinct genus of South American meridiungulatan ungulate, from the Late Paleocene to Late Eocene (Itaboraian to Tinguirirican in the SALMA classification) of South America (Argentina and Peru) and Antarctica (Seymour Island). It is the only member of the family Trigonostylopidae.

Astrapotheriidae is an extinct family of herbivorous South American land mammals that lived from the Late Eocene (Mustersan SALMA) to the Middle Miocene (Laventan SALMA) . The most derived of the astrapotherians, they were also the largest and most specialized mammals in the Tertiary of South America. There are two sister taxa: Eoastrapostylopidae and Trigonostylopidae.

Antarctodon is an extinct genus of mammals from the Early Eocene (late Ypresian age). It is a basal astrapotherian which lived in what is now Seymour Island, Antarctic Peninsula, at that moment still connected to South America where most of the astrapotherians were found. The holotype and only specimen MLP 08-XI-30-1, an isolated right p4 or m1, was found in the Telm 5 Member of the La Meseta Formation in West Antarctica. It was first named by Mariano Bond, Alejandro Kramarz, Ross D. E. MacPhee and Marcelo Reguero in 2011 and the type species is Antarctodon sobrali.

Eoastrapostylops is an extinct genus of astrapothere that lived during the Late Paleocene in what is now Argentina.