Moropus is an extinct genus of large perissodactyl mammal in the chalicothere family. They were endemic to North America during the Miocene from ~20.4—13.6 Mya, existing for approximately 6.8 million years. Moropus belonged to the schizotheriine subfamily of chalicotheres, and has the best fossil record of any member of this group; numbers of individuals, including complete skeletons, have been found.
Macrauchenia was a large, long-necked and long-limbed, three-toed native South American mammal in the order Litopterna. The genus gives its name to its family, the Macraucheniidae or "robust litopterns". Like other litopterns, it is most closely related to the odd-toed ungulates (Perissodactyla), from which litopterns diverged approximately 66 million years ago. The oldest fossils in the genus date to the late Miocene, around seven million years ago, and M. patachonica disappears from the fossil record during the late Pleistocene, around 20,000-10,000 years ago. M. patachonica is one of the last and best known member of the family and is known primarily from the Luján Formation in Argentina, but is known from localities across southern South America. Another genus of macraucheniid Xenorhinotherium was present in northeast Brazil and Venezuela during the Late Pleistocene. The type specimen was discovered by Charles Darwin during the voyage of the Beagle. In life, Macrauchenia may have resembled a humpless camel, though the two taxa are not closely related. It fed on plants in a variety of environments across what is now South America. Among the species described, M. patachonica and M. ullomensis are considered valid; M. boliviensis is considered a nomen dubium; and M. antiqua has been moved to the genus Promacrauchenia.
Peltephilus, the horned armadillo, is an extinct genus of dog-sized, armadillo xenarthran mammals which first inhabited Argentina during the Oligocene epoch, and became extinct in the Miocene epoch. Notably, the scutes on its head were so developed that they formed horns. Aside from the horned gophers of North America, it is the only known fossorial horned mammal.
Prosqualodon is an extinct genus of Early to Middle Miocene cetacean from Argentina, Australia, New Zealand and Venezuela.
Didolodus is an extinct genus of mammals from Middle Eocene Argentina. It is an ungulate mammal of uncertain affinities, possibly related to Litopterna, though this is uncertain due to the lack of reliable post-cranial remains, and for now remains Meridiungulata incertae sedis. Its remains were found in the Sarmiento Formation of Patagonia.
Diadiaphorus is an extinct genus of litoptern mammal from the Miocene of Argentina and Bolivia, South America.
Theosodon is an extinct genus of litoptern mammal from the Early to Middle Miocene of South America.
Notostylops is a genus of extinct South American ungulates from Eocene Argentina. Fossils of the genus have been found in the Sarmiento, Casamayor, Andesitas Huancache and Koluel Kaike Formations.
Thomashuxleya is an extinct genus of notoungulate mammal, named after famous 19th-century biologist Thomas Huxley.
Rhynchippus is an extinct genus of notoungulate mammals from the Late Oligocene of South America. The genus was first described by Florentino Ameghino in 1897 and the type species is R. equinus, with lectotype MACN A 52–31. Fossils of Rhynchippus have been found in the Agua de la Piedra and Sarmiento Formations of Argentina, the Salla and Petaca Formations of Bolivia, the Tremembé Formation of Brazil, and the Moquegua Formation of Peru.
Scarrittia is an extinct genus of hoofed mammal of the family Leontiniidae, native to South America during the Late Oligocene epoch.
Homalodotherium is an extinct genus of notoungulate mammals native to South America. Fossils of Homalodotherium have been found in the Middle Miocene Santa Cruz Formation of Argentina and the Río Frías Formation of Chile.
Adinotherium is an extinct genus of Toxodontidae, large bodied hoofed ungulates which inhabited South America during the Middle to Late Miocene, from 17.5 to 6.8 Ma and existed for approximately 10.7 million years, Santacrucian to Huayquerian in the South American land mammal ages (SALMA). Fossils of Adinotherium have been found in the Santa Cruz and Ituzaingó Formations of Argentina and the Chucal and Río Frías Formations of Chile.
Tremacebus is an extinct genus of New World monkeys from the Early Miocene. The type species is T. harringtoni.
Pucapristis is a prehistoric genus of sclerorhynchid ray whose fossils first appear in the fossil record in rocks dating from the Maastrichtian stage. The genus was described in 1963 by Schaeffer. Fossils of Pucapristis have not been found in any subsequent strata. Incidentally, the Maastrichtian is the final portion of the Cretaceous Period and its endpoint marks the advent of the Cretaceous–Paleogene extinction event. This major geological transition is famous for being the mass extinction that wiped out the dinosaurs.
Proterotheriidae is an extinct family of fossil ungulates from the Cenozoic era that displays toe reduction. Despite resembling primitive, small horses, they were only distantly related to them, and instead belonged to the native South American ungulate order Litopterna.
Propalaehoplophorus, also written as Propalaeohoplophorus, is an extinct genus of glyptodont, which lived in South America during the Early Miocene epoch.
Neolicaphrium is an extinct genus of ungulate mammal belonging to the extinct order Litopterna. This animal lived from the Late Pliocene (Chapadmalalan) to the Late Pleistocene (Lujanian) in southern South America, being the last survivor of the family Proterotheriidae.
Megadolodus is an extinct genus of proterotheriid litopterns.
Prolicaphrium is an extinct genus of proterotheriid litoptern that lived during the Early Miocene, in what is now Argentina. Fossils have been found in the Sarmiento Formation of Argentina.
