extinct Extinction is the termination of a kind of organism or of a group of kinds (taxon), usually a species. The moment of extinction is generally considered to be the death of the last individual of the species, although the capacity to breed and ...

Cenozoic The Cenozoic ( ; ) is Earth's current geological era, representing the last 66million years of Earth's history. It is characterised by the dominance of mammals, birds and flowering plants, a cooling and drying climate, and the current configura ...

horses The horse (''Equus ferus caballus'') is a domesticated, one-toed, hoofed mammal. It belongs to the taxonomic family Equidae and is one of two extant subspecies of ''Equus ferus''. The horse has evolved over the past 45 to 55 million yea ...

Litopterna 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 the G ...

Neolicaphrium ''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 t ...

Diadiaphorus ''Diadiaphorus'' is an extinct genus of litoptern mammal from the Miocene of Argentina ( Ituzaingó, Pinturas, Chiquimil and Santa Cruz Formations) and Bolivia ( Nazareno Formation), South America. Description ''Diadiaphorus'' closely rese ...

Thoatherium ''Thoatherium'' (meaning "active swift-beast") is an extinct genus of litoptern mammals from the Early Miocene of Argentina. Fossils of the genus have been found in the Santa Cruz Formation in Argentina.

Taxonomy

* Proterotheriidae ** ''

Anisolambda ''Anisolambda'' is an extinct genus of litoptern. It lived from the Late Paleocene to the Middle Eocene in what is now Argentina. Description This animal is mostly known from fossils of its maxilla, mandible and teeth, and it is therefore diff ...

'' ** ''

Anisolophus ''Anisolophus'' is an extinct genus of proterotheriid from the Early to Middle Miocene of Argentina. The genus was named by Burmeister in 1885 to accommodate the species ''Anchitherium australe'', which they had named earlier in 1879. Soria then ...

'' ** ''

Brachytherium ''Brachytherium'' is an extinct genus of proterotheriid mammal from the Late Miocene to Late Pliocene of Argentina. It is represented by the type and only species ''B. cuspidatum'', a taxon named in 1883 by Ameghino for a partial mandible with t ...

'' ** ''

Diadiaphorus ''Diadiaphorus'' is an extinct genus of litoptern mammal from the Miocene of Argentina ( Ituzaingó, Pinturas, Chiquimil and Santa Cruz Formations) and Bolivia ( Nazareno Formation), South America. Description ''Diadiaphorus'' closely rese ...

'' ** ''

Diplasiotherium ''Diplasiotherium'' is an extinct genus of litoptern belonging to the family Proterotheriidae, that lived between the late Miocene and the early Pliocene (in the SALMAs Huayquerian and Montehermosan).Villafañé et al., 2006, p.161 The fossils o ...

'' ** ''

Eoauchenia ''Eoauchenia'' is a genus of extinct proterotheriidae, proterotheriid from the Late Miocene and Early Pliocene of Argentina. The genus was named by Ameghino in 1887 for the type species ''E. primitiva'', which was originally known from the early ...

'' ** '' Eolicaphrium'' ** '' Epecuenia'' ** ''

Epitherium ''Epitherium'' is an extinct genus of Litopterna, who belonged to the family Proterotheriidae. It lived during the Pliocene in South America. The fossils of this herbivorous ungulate were found in Argentina Argentina (), officially the ...

'' ** ''

Guilielmofloweria ''Guilielmofloweria'' is an extinct genus of proterotheriid litoptern that lived from the Middle to Late Eocene of what is now Argentina. Fossils have been found in the Sarmiento Formation of Argentina. Taxonomy ''Guilielmofloweria'' was firs ...

'' ** '' Heteroglyphis'' ** ''

Lambdaconus ''Lambdaconus'' is a genus of proterotheriid from the Late Oligocene to Early Miocene of Argentina. The type species is ''L. suinus'', named in 1897 by Ameghino, with referred species including ''L. lacerum'', named as ''Proterotherium ''Prot ...

'' ** '' Lambdaconops'' ** ''

Mesolicaphrium ''Mesolicaphrium'' is a genus of extinct litoptern from the late middle Miocene of southern Colombia. It was named in 2020 by Andrew McGrath and colleagues, for the species previously classified as '' Prolicaphrium sanalfonensis'' from the La Vi ...

'' ** ''

Neobrachytherium ''Neobrachytherium'' is an extinct genus of proterotheriid mammal from the Late Miocene of Argentina and Uruguay. It is represented by multiple species, including the type ''N. intermedium'', originally named in 1891 by Moreno and Mercerat as a ...

'' ** ''

Neodolodus ''Neodolodus'' is a genus of extinct litoptern from the late middle Miocene of southern Colombia. It was named in 1986 by Hoffstetter and Soria, for the species ''Neodolodus colombianus'' from the Castilletes Formation and the La Victoria and Vi ...

'' ** ''

Neolicaphrium ''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 t ...

'' ** ''

Olisanophus ''Olisanophus'' is a genus of extinct litoptern from the late middle Miocene of southern Bolivia. It was named in 2020 by Andrew McGrath and colleagues, for two distinct species from the same deposits of an unnamed formation of the Honda Group. ...

'' ** ''

Paramacrauchenia ''Paramacrauchenia'' is an extinct genus of proterotheriid litopterns from the Early Miocene of what is now Argentina and Chile. Its fossils have been found in the Sarmiento and Santa Cruz Formations of Argentina and Chile. Taxonomy ''Paramac ...

'' ** ''

Paranisolambda ''Paranisolambda'' is an extinct genus of proterotheriid litopterns from the Early to Middle Eocene of Brazil. Fossils of ''Paranisolambda'' have been recovered from the Itaboraí Formation in the Brazilian state of Rio de Janeiro Rio de J ...

'' ** ''

Picturotherium ''Picturotherium'' is a genus of extinct proterotheriid from the middle Miocene of Santa Cruz, Argentina. The genus is known from the type and only species ''P. migueli'', named in 2005 by Alejandro Kramarz and Mariano Bond for individual teeth ...

'' ** ''

Prolicaphrium ''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. Description This animal may have been vaguely si ...

'' ** ''

Proterotherium ''Proterotherium'' (meaning "first beast") is an extinct genus of litoptern mammal of the family Proterotheriidae that lived during the Late Miocene of Argentina and Chile. Fossils of this genus have been found in the Ituzaingó Formation of Arge ...

'' ** ''

Protheosodon ''Protheosodon'' is an extinct genus of proterotheriid litoptern. It lived from the Late Oligocene to the Early Miocene in what is now Argentina and Colombia. Description It was a medium-sized animal, smaller than the extant vicuña. The low ...

'' ** ''

Pseudobrachytherium ''Pseudobrachytherium'' is an extinct genus of proterotheriid from the Late Miocene of Uruguay. It is only known from the type species ''P. breve'', named in 2020 by Corona and colleagues for an almost complete skull found in the greenish peli ...

'' ** ''

Tetramerorhinus ''Tetramerorhinus'' is an extinct genus of proterotheriid litoptern that lived during the Early and Middle Miocene in what is now Argentina and Peru. Description This animal resembled a small horse, with slender, elongated legs. The body was a ...

'' ** ''

Thoatherium ''Thoatherium'' (meaning "active swift-beast") is an extinct genus of litoptern mammals from the Early Miocene of Argentina. Fossils of the genus have been found in the Santa Cruz Formation in Argentina.Thoatheriopsis ''Thoatheriopsis'' is an extinct genus of proterotheriid from the Miocene of Mendoza Province, Argentina. The taxon is known only from the specimen MLP 81-XI-28-1, which includes an upper tooth row, and was named as the new binomial ''Thoatherio ...

'' ** ''

Villarroelia ''Villarroelia'' is an extinct genus of proterotheriid from the Middle Miocene of Colombia. Etymology The genus name, ''Villarroelia'' refers to the paleontologist Carlos Villarroel, for his contributions to the understanding of prehistoric S ...

'' ** '' Uruguayodon'' ** ''

Wainka ''Wainka'' is an extinct genus of South American mammal, belonging to the order Litopterna. It lived during the Middle Paleocene. Description This animal is only known for a few teeth. The upper molars were almost triangular in shape, elongated, ...

'' ** '' Xesmodon'' ** Megadolodinae *** ''

Bounodus ''Bounodus'' is an extinct genus of ungulates native from South America, belonging to the order Litopterna. Its remains were found in Miocene rocks from the Urumaco Formation of northern Venezuela. The genus is only known from its holotype ...

'' *** ''

Megadolodus ''Megadolodus'' is an extinct genus of proterotheriid litopterns. History The first fossils of ''Megadolodus'' were uncovered from the Villavieja Formation, in the fossil locality La Venta, in what is today Colombia, in terrains dated from ...

'' ** Indaleciidae *** ''

Adiantoides ''Adiantoides'' is an extinct genus of herbivorous mammal, belonging to the order Litopterna. It lived during the Middle to Late Eocene, in South America. Description It was a small-sized animal, only slightly larger than a cat. The skull wa ...

'' *** '' Indalecia'' Proterotheriidae is traditionally considered to include two subfamilies, Anisolambdinae and Proterotheriinae. Anisolambdinae (also called Anisolambdidae in some studies) was proposed to unite the primitive and earlier forms ''

Anisolambda ''Anisolambda'' is an extinct genus of litoptern. It lived from the Late Paleocene to the Middle Eocene in what is now Argentina. Description This animal is mostly known from fossils of its maxilla, mandible and teeth, and it is therefore diff ...

'', '' Eolicaphrium'', ''

Paranisolambda ''Paranisolambda'' is an extinct genus of proterotheriid litopterns from the Early to Middle Eocene of Brazil. Fossils of ''Paranisolambda'' have been recovered from the Itaboraí Formation in the Brazilian state of Rio de Janeiro Rio de J ...

'', ''

Protheosodon ''Protheosodon'' is an extinct genus of proterotheriid litoptern. It lived from the Late Oligocene to the Early Miocene in what is now Argentina and Colombia. Description It was a medium-sized animal, smaller than the extant vicuña. The low ...

'', ''

Guilielmofloweria ''Guilielmofloweria'' is an extinct genus of proterotheriid litoptern that lived from the Middle to Late Eocene of what is now Argentina. Fossils have been found in the Sarmiento Formation of Argentina. Taxonomy ''Guilielmofloweria'' was firs ...

'', '' Heteroglyphis'', '' Lambdaconops'', ''

Wainka ''Wainka'' is an extinct genus of South American mammal, belonging to the order Litopterna. It lived during the Middle Paleocene. Description This animal is only known for a few teeth. The upper molars were almost triangular in shape, elongated, ...

'' and '' Xesmodon''. However, the phylogenetic analysis of McGrath and colleagues recovered the included genera to neither form their own clade, or to universally represent basal taxa outside the genera of Proterotheriinae per Soria, making Anisolambdinae a polyphyletic group of unrelated organisms. Proterotheriidae was redefined by McGrath and colleagues in 2019 to be all taxa closer to ''

Tetramerorhinus ''Tetramerorhinus'' is an extinct genus of proterotheriid litoptern that lived during the Early and Middle Miocene in what is now Argentina and Peru. Description This animal resembled a small horse, with slender, elongated legs. The body was a ...

'' than ''

Macrauchenia ''Macrauchenia'' ("long llama", based on the now-invalid llama genus, ''Auchenia'', from Greek "big neck") 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 ...

'', ''

Tricoelodus ''Tricoelodus'' is an extinct genus of adianthid litopterns that lived during the Late Oligocene in what is now Argentina and Bolivia. Fossils of this genus have been found in the Sarmiento Formation of Argentina and the Salla Formation of Bol ...

'' or ''

Protolipterna ''Protolipterna'' is an extinct genus of mammal, belonging to the order Litopterna. It lived during the Late Paleocene and the Early Eocene, in what is now South America. Description It was a small-sized animal, not exceeding 35 centimeter ...

''. The cladogram below shows the modified results of their phylogenetic analysis, where incomplete taxa were placed based on morphology. The unrelated genera of the polyphyletic taxon Anisolambdinae or Anisolambdidae is highlighted in pink.

References

{{Taxonbar, from=Q138661 Litopterns Prehistoric mammal families Paleocene first appearances Holocene extinctions Pleistocene mammals of South America Neogene mammals of South America Paleogene mammals of South America Taxa named by Florentino Ameghino