''Proterotherium'' (meaning "first beast") is an extinct genus of

litoptern Litopterna (from grc, λῑτή πτέρνα "smooth heel") is an extinct order of fossil hoofed mammals from the Cenozoic era. The order is one of the five great orders of South American ungulates that were endemic to the continent, until th ...

mammal of the family

Proterotheriidae Proterotheriidae is an extinction, 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 Sou ...

that lived during the Late

Miocene The Miocene ( ) is the first epoch (geology), geological epoch of the Neogene Period and extends from about (Ma). The Miocene was named by Scottish geologist Charles Lyell; the name comes from the Greek words (', "less") and (', "new") and mea ...

Argentina Argentina (), officially the Argentine Republic ( es, link=no, República Argentina), is a country in the southern half of South America. Argentina covers an area of , making it the second-largest country in South America after Brazil, th ...

and

Chile Chile, officially the Republic of Chile, is a country in the western part of South America. It is the southernmost country in the world, and the closest to Antarctica, occupying a long and narrow strip of land between the Andes to the east a ...

. Fossils of this genus have been found in the

Ituzaingó Formation The Ituzaingó Formation ( es, Formación Ituzaingó), in older literature also described as Entre Ríos or Entrerriana Formation, is an extensive geological formation of Late Miocene (Tortonian, or Huayquerian in the SALMA classification) age i ...

of Argentina, and the Galera Formation of Chile.

Classification

The genus ''Proterotherium'' was first described by Florentino Ameghino in 1883, on the basis of fossil remains found in Upper Miocene deposits in Patagonia. The type species is ''Proterotherium cervioides''. Numerous other species have been ascribed to this genus, many of which come from lower-middle Miocene deposits, such as ''P. americanum'', ''P. australe'', ''P. brachygnathum'', ''P. cavum'', ''P. cingulatum'', ''P. curtidens'', ''P. dichotomum'' , ''P. divortium'', ''P. gradatum'', ''P. intermedium'', ''P. karaikense'', ''P. mixtum'', ''P. nitens'', ''P. perpolitum'', ''P. politum'', ''P. main'', and ''P. pyramidatum''. However, many of these species are now considered to be synonymous with the type species, and others belong to other genera, such as '' Tetramerorhinus'', a genus long confused with ''Proterotherium''. ''Proterotherium'' is the type genus of Proterotheriidae, a group of litopterns characterized by a morphology very similar to that of equids, especially in regards to the legs. ''Proterotherium'' is a typical example of the Miocene proterotheres, very specialized in the morphology of the legs and also in the dentition. A very similar animal was ''Anisolophus''.

Cladogram A cladogram (from Greek ''clados'' "branch" and ''gramma'' "character") is a diagram used in cladistics to show relations among organisms. A cladogram is not, however, an evolutionary tree because it does not show how ancestors are related to ...

based in the

phylogenetic analysis In biology, phylogenetics (; from Greek φυλή/ φῦλον [] "tribe, clan, race", and wikt:γενετικός, γενετικός [] "origin, source, birth") is the study of the evolutionary history and relationships among or within groups o ...

published by McGrath ''et al.'', 2020, showing the position of ''Proterotherium'':

References

{{Taxonbar, from=Q9063287 Proterotheriids Miocene mammals of South America Huayquerian Neogene Argentina Fossils of Argentina Neogene Chile Fossils of Chile Taxa named by Florentino Ameghino Fossil taxa described in 1883 Ituzaingó Formation Prehistoric placental genera