Toxodon is an extinct genus of large ungulate native to South America from the Late Miocene to early Holocene epochs. Toxodon is a member of Notoungulata, an order of extinct South American native ungulates distinct from the two living ungulate orders that had been indigenous to the continent for over 60 million years since the early Cenozoic, prior to the arrival of living ungulates into South America around 2.5 million years ago during the Great American Interchange. Toxodon is a member of the family Toxodontidae, which includes medium to large sized herbivores. Toxodon was one of the largest members of Toxodontidae and Notoungulata, with Toxodon platensis having an estimated body mass of 1,000–1,200 kilograms (2,200–2,600 lb).
Toxodontia is a suborder of the meridiungulate order Notoungulata. Most of the members of the five included families, including the largest notoungulates, share several dental, auditory and tarsal specializations. The group is named after Toxodon, the first example of the group to be discovered by science.
South American native ungulates, commonly abbreviated as SANUs, are extinct ungulate-like mammals of controversial affinities that were indigenous to South America prior to the Great American Biotic Interchange. They comprise five major groups conventionally ranked as orders—Astrapotheria, Litopterna, Notoungulata, Pyrotheria, and Xenungulata—as well as the primitive "condylarth" groups Didolodontidae and Kollpaniinae. It has been proposed that some or all of the members of this group form a clade, named Meridiungulata, though the relationships of South American ungulates remain largely unresolved. The two largest groups of South American ungulates, the notoungulates and the litopterns, were the only groups to persist beyond the mid Miocene. Only a few of the largest species of notoungulates and litopterns survived until the end-Pleistocene extinction event around 12,000 years ago where they became extinct with most other large mammals in the Americas, shortly after the first arrival of humans into the region.
Leontiniidae is an extinct family comprising eighteen genera of notoungulate mammals known from the Middle Eocene (Mustersan) to Late Miocene (Huayquerian) of South America.
Toxodontidae is an extinct family of notoungulate mammals, known from the Oligocene to the Holocene of South America, with one genus, Mixotoxodon, also known from the Pleistocene of Central America and southern North America. Member of the family were medium to large-sized, ranging from around 350–400 kilograms (770–880 lb) in Nesodon to 1,000–1,200 kilograms (2,200–2,600 lb) in Toxodon, and had medium to high-crowned dentition, which in derived members of the group evolved into ever-growing cheek teeth. Isotopic analyses have led to the conclusion that Pleistocene members of the family were flexible mixed feeders.
Mesotheriidae is an extinct family of notoungulate mammals known from the Oligocene through the Pleistocene of South America. Mesotheriids were small to medium-sized herbivorous mammals adapted for digging.
Mixotoxodon is an extinct genus of notoungulate of the family Toxodontidae inhabiting South America, Central America and parts of southern North America during the Pleistocene epoch, from 1,800,000—12,000 years ago.
Typotheria is a suborder of the extinct mammalian order Notoungulata and includes five families: Archaeopithecidae, Campanorcidae, Interatheriidae, Mesotheriidae, and Oldfieldthomasiidae. Cifelli indicated that Typotheria would be paraphyletic if it excluded members of the suborder Hegetotheria and he advocated inclusion of the hegetothere families Archaeohyracidae and Hegetotheriidae in Typotheria.
Mesotherium is an extinct genus of mesotheriid, a long-lasting family of superficially rodent-like, burrowing notoungulates from South America. It one of the youngest notoungulates, and the last known member of Typotheria. It was first named by Étienne Serres in 1867, and only contains a single species, Mesotherium cristatum, spanning the Early-Middle Pleistocene.
Huilatherium is an extinct genus of leontiniid, a group of hoofed mammals belonging to the order Notoungulata, that comprises other South American ungulate families that evolved in parallel with some mammals of the Northern hemisphere. The leontiinids were a family of herbivorous species comprising medium to large browsers, with relatively short skulls and robust limbs, somewhat similar to their relatives, the best known toxodontids.
Piauhytherium is an extinct genus of herbivorous notoungulate mammal of the family Toxodontidae. It lived during the Late Pleistocene; fossils have been found in Brazil. The only known species is Piauhytherium capivarae.
Fiandraia is an extinct monotypic genus of notoungulate that lived in Uruguay during the Oligocene and the Early Miocene. It was found in the Fray Bentos Formation, in rocks dated back from the Deseadan period.
Eohyrax is an extinct genus of Notoungulate, belonging to the suborder Typotheria. It lived during the Middle Eocene, and its remains were discovered in South America.
Pseudotypotherium is an extinct genus of Notoungulates, belonging to the suborder Typotheria. It lived from the Late Miocene to the Late Pliocene, and its fossilized remains were discovered in South America.
Plesiotypotherium is an extinct genus of Notoungulate, belonging to the suborder Typotheria. It lived from the Middle to the Late Miocene, and its fossilized remains were discovered in South America.
Colbertia is an extinct genus of oldfieldthomasiid notoungulate. It lived from the Early to the Middle Eocene, and its fossilized remains were discovered in Argentina and Brazil.
Oldfieldthomasia is an extinct genus of Notoungulate, probably related to the suborder Typotheria. It lived during the Middle Eocene, in what is today South America.
Ultrapithecus is an extinct genus of oldfieldthomasiid notoungulate that lived during the Middle Eocene of what is now Argentina.
Notopithecus is an extinct genus of Notoungulate, belonging to the suborder Typotheria. It lived from the Middle to the Late Eocene and its fossilized remains were discovered in South America.
Rosendo is an extinct genus of notohippid notoungulates that lived during the Early Oligocene in what is now Argentina and Chile. Fossils of this genus have been found in the Sarmiento Formation and the Abanico Formations of Argentina and Chile.
Restoration of Thomashuxleya , an early toxodontian notoungulate from the Eocene (Lutetian) of Argentina
Skull of Hegetotherium (Typotheria, Hegetotheriidae)
Skull of Mesotherium (Typotheria, Mesotheriidae)
Skeleton of Miocochilius (Typotheria, Interatheriidae)
Skeleton of Nesodon (Toxodontia, Toxodontidae)
Skeleton of Protypotherium (Typotheria, Interatheriidae)
Skeleton of Pachyrukhos (Typotheria, Hegetotheriidae)
Skeleton of Homalodotherium (Toxodontia, Homalodotheriidae)
Rhynchippus (Toxodontia, Notohippidae)
Scarrittia (Toxodontia, Leontiniidae)
