Eocene mammals of Antarctica

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.

Polydolopimorphia is an extinct order of metatherians, closely related to extant marsupials. Known from the Paleocene-Pliocene of South America and the Eocene of Antarctica, they were a diverse group during the Paleogene, filling many niches, before declining and becoming extinct at the end of the Neogene. It is divided into two suborders, Bonapartheriiformes, and Polydolopiformes Most members are only known from jaw fragments, which have their characteristically generally bunodont teeth. The morphology of their teeth has led to proposals that polydolopimorphians may be crown group marsupials,

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.

Llanocetus ( "Llano's whale" ) is a genus of extinct toothed baleen whales from the Late Eocene of Antarctica and New Zealand. The type species, Llanocetus denticrenatus, reached gigantic proportions, with the juvenile specimen reaching an estimated in length; a second, unnamed species, known only from three isolated premolar teeth, reached an estimated total body length of up to . Like other contemporary baleen whales of the Eocene, Llanocetus completely lacked baleen in its jaws. It was probably a suction feeder like the modern beaked and pygmy right whales.