Sparassodonta is an extinct order of carnivorous metatherian mammals native to South America, related to modern marsupials. They were once considered to be true marsupials, but are now thought to be a separate side branch that split before the last common ancestor of all modern marsupials. A number of these mammalian predators closely resemble placental predators that evolved separately on other continents, and are cited frequently as examples of convergent evolution. They were first described by Florentino Ameghino, from fossils found in the Santa Cruz beds of Patagonia. Sparassodonts were present throughout South America's long period of "splendid isolation" during the Cenozoic; during this time, they shared the niches for large warm-blooded predators with the flightless terror birds. Previously, it was thought that these mammals died out in the face of competition from "more competitive" placental carnivorans during the Pliocene Great American Interchange, but more recent research has showed that sparassodonts died out long before eutherian carnivores arrived in South America. Sparassodonts have been referred to as borhyaenoids by some authors, but currently the term Borhyaenoidea refers to a restricted subgroup of sparassodonts comprising borhyaenids and their close relatives.
Thylacosmilus is an extinct genus of saber-toothed metatherian mammals that inhabited South America from the Late Miocene to Pliocene epochs. Though Thylacosmilus looks similar to the "saber-toothed cats", it was not a felid, like the well-known North American Smilodon, but a sparassodont, a group closely related to marsupials, and only superficially resembled other saber-toothed mammals due to convergent evolution. A 2005 study found that the bite forces of Thylacosmilus and Smilodon were low, which indicates the killing-techniques of saber-toothed animals differed from those of extant species. Remains of Thylacosmilus have been found primarily in Catamarca, Entre Ríos, and La Pampa Provinces in northern Argentina.
Borhyaena is an extinct genus of South American metatherian, living between 17.5 and 15.5 million years ago in Patagonia, Argentina and Chile.
Protypotherium is an extinct genus of notoungulate mammals native to South America during the Oligocene and Miocene epochs. A number of closely related animals date back further, to the Eocene. Fossils of Protypotherium have been found in the Deseadan Fray Bentos Formation of Uruguay, Muyu Huasi and Nazareno Formations of Bolivia, Cura-Mallín and Río Frías Formations of Chile, and Santa Cruz, Salicas, Ituzaingó, Aisol, Cerro Azul, Cerro Bandera, Cerro Boleadoras, Chichinales, Sarmiento and Collón Curá Formations of Argentina.
Cramauchenia is an extinct genus of litoptern South American ungulate. Cramauchenia was named by Florentino Ameghino. The name has no literal translation. Instead, it is an anagram of the name of a related genus Macrauchenia. This genus was initially discovered in the Sarmiento Formation in the Chubut Province, in Argentina, and later it was found in the Chichinales Formation in the Río Negro Province and the Cerro Bandera Formation in Neuquén, also in Argentina, in sediments assigned to the SALMA Colhuehuapian, as well as the Agua de la Piedra Formation in Mendoza, in sediments dated to the Deseadan. In 1981 Soria made C. insolita a junior synonym of C. normalis. A specimen of C. normalis was described in 2010 from Cabeza Blanca in the Sarmiento Formation, in sediments assigned to the Deseadan SALMA.
Cyonasua is an extinct genus of procyonid from the Late Miocene to Middle Pleistocene of South America. Fossils of Cyonasua have been found in Argentina, Bolivia, Uruguay, and Venezuela. The oldest well-dated fossils of Cyonasua are approximately 7.3 million years old. Most fossils of Cyonasua are late Miocene to early late Pliocene in age, but a single early Pleistocene specimen indicates that members of this genus survived until at least 0.99 million years ago.
Anachlysictis gracilis is an extinct carnivorous mammal belonging to the group Sparassodonta, which were metatherians that inhabited South America during the Cenozoic. Anachlysictis is the first record of such borhyaenoids in northern South America, and also the most primitive known member of the family Thylacosmilidae, a group of predators equipped with "saber teeth". It was also the only confirmed record of a thylacosmilid that did not belong to the genus Thylacosmilus until the official publication of Patagosmilus in 2010.
Dukecynus is an extinct genus of meat-eating metatherian belonging to the order Sparassodonta, which lived in South America during the Middle Miocene (Laventan), between about 13.8 and 11.8 million years ago. The name of the genus meaning "Duke dog", for Duke University and the Greek word cynos, dog, for the pretended similarity of this animal with dogs. A single species known so far, Dukecynus magnus. The species name "magnus" derives from Latin for big, to reflect their great size.
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. The largest species, Proborhyaena gigantea, is estimated to be about the size of a spectacled bear, with its skull reaching 60 cm (2.0 ft) in length, and body mass estimates up to approximately 90–200 kg (200–440 lb), making the proborhyaenids some of the largest known metatherians. Proborhyaenid remains have been found in western Bolivia, Uruguay, southern Brazil, and the provinces of Mendoza, Salta, and Chubut, in Argentina.
Thylacosmilidae is an extinct family of metatherian predators, related to the modern marsupials, which lived in South America between the Miocene and Pliocene epochs. Like other South American mammalian predators that lived prior to the Great American Biotic Interchange, these animals belonged to the order Sparassodonta, which occupied the ecological niche of many eutherian mammals of the order Carnivora from other continents. The family's most notable feature are the elongated, laterally flattened fangs, which is a remarkable evolutionary convergence with other saber-toothed mammals like Barbourofelis and Smilodon.
Stagodontidae is an extinct family of carnivorous metatherian mammals that inhabited North America and Europe during the late Cretaceous, and possibly to the Eocene in South America.
Pharsophorus is an extinct genus of borhyaenoid sparassodont that inhabited South America during the Middle to Late Oligocene epoch.
Patagosmilus is an extinct genus of meat-eating metatherian mammal of the family Thylacosmilidae, that lived in the Middle Miocene in South America. Like other representatives of this family, such as Thylacosmilus atrox and Anachlysictis gracilis, it was characterized by its elongated fangs of the upper jaw, similar to the well known "sabertooth cats" (Machairodontinae), of which they were ecological equivalents. Despite being geologically younger than Anachlysictis, the morphology of Patagosmilus suggests that this species was more closely related to Thylacosmilus than Anachlysictis, though in other respects this species is less specialized than Thylacosmilus.
Groeberiidae is a family of strange non-placental mammals from the Eocene and Oligocene epochs of Patagonia, Argentina and Chile, South America. Originally classified as paucituberculate marsupials, they were suggested to be late representatives of the allothere clade Gondwanatheria. However, the relationship of the type genus, Groeberia, to Gondwanatheria has been firmly rejected by other scholars.
Promacrauchenia is an extinct genus of macraucheniids that lived during the Late Miocene to Late Pliocene epochs of what is now Argentina and Bolivia. It belongs to the subfamily Macraucheniinae, which also includes Huayqueriana, Macrauchenia, and Xenorhinotherium. Fossils of this genus have been found in the Ituzaingó, Andalhuala, and Cerro Azul Formations of Argentina.
Fredszalaya is an extinct genus of omnivorous mammal, belonging to the order Sparassodonta. It lived during the Late Oligocene, and its fossilized remains were discovered in South America.
Australohyaena is an extinct genus of carnivorous mammal, belonging to the order Sparassodonta. It lived during the Late Oligocene, and its fossilized remains were discovered in Argentina.
Arminiheringia is an extinct genus of sparassodont. It lived during the Early Eocene in South America.
Paraborhyaena is an extinct genus of Sparassodont, belonging to the family Proborhyaenidae. It was one of the large terrestrial predators that roamed South America during the Oligocene.
Proborhyaena is an extinct genus of proborhyaenid sparassodont that lived during the Oligocene of what is now South America. It is considered to be the largest of the sparassodonts.
