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.
Chapalmalania is an extinct genus of procyonid from the Late Miocene or Early Pliocene to Early Pleistocene of Argentina, Venezuela, and Colombia.
Borhyaenidae is an extinct metatherian family of low-slung, heavily built predatory mammals in the order Sparassodonta. Borhyaenids are not true marsupials, but members of a sister taxon, Sparassodonta. Like most metatherians, borhyaenids and other sparassodonts are thought to have had a pouch to carry their offspring around. Borhyaenids had strong and powerful jaws, like those of the unrelated placentalians Hyaenodon and Andrewsarchus, for crushing bones. Borhyaenids grew up to an average of 5 to 6 feet long.
La Venta is a fossil locality located in the modern departments of Tolima and Huila in Colombia. This site is one of the richest Neogene fossil assemblages in South America and represents the best-known Cenozoic fossil site outside of Argentina. It provides a glimpse of what life in the region was like before the main wave of the Great American Interchange.
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.
Langstonia is an extinct genus of notosuchian crocodylomorph of the family Sebecidae. It lived in the middle Miocene, in the "Monkey Beds" of the Colombian Villavieja Formation. Langstonia was named in 2007 by Alfredo Paolillo and Omar Linares for fossils originally described by Langston in 1965 as Sebecus huilensis. Thus, the type species is L. huilensis.
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.
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.
Lycopsis is an extinct genus of South American metatherian that lived during the Miocene in Argentina and Colombia.
Hondadelphys is an extinct genus of carnivorous sparassodonts, known from the Middle Miocene of Colombia. The type species, H. fieldsi, was described in 1976 from the fossil locality of La Venta, which hosts fossils from the Villavieja Formation. Hondadelphys was originally interpreted as belonging to the opossum family Didelphidae, but subsequently assigned to its own family, Hondadelphidae and interpreted as a basal sparassodont. The genus name refers to the Honda Group, the stratigraphic group in which the fossils of this animal were first found, combined with delphys (Greek for "womb", a common suffix used for opossum-like metatherians).
Anatoliadelphys maasae is an extinct genus of predatory metatherian mammal from the Eocene of Anatolia. It was an arboreal, cat-sized animal, with powerful crushing jaws similar to those of the modern Tasmanian devil. Although most mammalian predators of the northern hemisphere in this time period were placentals, Europe was an archipelago, and the island landmass now forming Turkey might have been devoid of competing mammalian predators, though this may not matter since other carnivorous metatherians are also known from the Cenozoic in the Northern Hemisphere. Nonetheless, it stands as a reminder that mammalian faunas in the Paleogene of the Northern Hemisphere were more complex than previously thought, and metatherians did not immediately lose their hold as major predators after their success in the Cretaceous.
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.
Magdalenabradys is an extinct genus of mylodontid ground sloths that lived during the Middle Miocene and Early Pliocene of what is now Colombia and Venezuela. Fossils have been found in the Villavieja Formation of the Honda Group in Colombia, and the Codore and Urumaco Formations of Venezuela.
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.
