Litopterna (from "smooth heel") is an

extinct Extinction is the termination of an organism by the death of its Endling, last member. A taxon may become Functional extinction, functionally extinct before the death of its last member if it loses the capacity to Reproduction, reproduce and ...

order of

South American native ungulates South American native ungulates, commonly abbreviated as SANUs, are extinct ungulate-like mammals that were indigenous to South America from the Paleocene (from at least 63 million years ago) until the end of the Late Pleistocene (~12,000 years a ...

that lived from the

Paleocene The Paleocene ( ), or Palaeocene, is a geological epoch (geology), epoch that lasted from about 66 to 56 mya (unit), million years ago (mya). It is the first epoch of the Paleogene Period (geology), Period in the modern Cenozoic Era (geology), ...

to the

Pleistocene The Pleistocene ( ; referred to colloquially as the ''ice age, Ice Age'') is the geological epoch (geology), epoch that lasted from to 11,700 years ago, spanning the Earth's most recent period of repeated glaciations. Before a change was fin ...

Holocene The Holocene () is the current geologic time scale, geological epoch, beginning approximately 11,700 years ago. It follows the Last Glacial Period, which concluded with the Holocene glacial retreat. The Holocene and the preceding Pleistocene to ...

around 62.5 million to 12,000 years ago (or possibly as late as 3,500 years ago), and were also present in Antarctica during the

Eocene The Eocene ( ) is a geological epoch (geology), epoch that lasted from about 56 to 33.9 million years ago (Ma). It is the second epoch of the Paleogene Period (geology), Period in the modern Cenozoic Era (geology), Era. The name ''Eocene'' comes ...

. They represent the second most diverse group of South American ungulates after

Notoungulata Notoungulata is an extinct order of ungulates that inhabited South America from the early Paleocene to the end of the Pleistocene, living from approximately 61 million to 11,000 years ago. Notoungulates were morphologically diverse, with forms re ...

. It is divided into nine families, with

Proterotheriidae Proterotheriidae is an extinction, extinct family of Litopterna, litoptern ungulates known from the Eocene-Late Pleistocene of South America. Members of the group were small-medium sized cursorial Herbivore, herbivores with brachydont Tooth, teet ...

and

Macraucheniidae Macraucheniidae is a family in the extinct South American ungulate order Litopterna, that resembled camelids. They had three functional digits on the fore and hind feet, as well as elongate necks. The family is generally divided up into two sub ...

being the most diverse and last surviving families.

Diversity

The body forms of many litopterns, notably in the limb and skull structure, are broadly similar to those of living

ungulate Ungulates ( ) are members of the diverse clade Euungulata ("true ungulates"), which primarily consists of large mammals with Hoof, hooves. Once part of the clade "Ungulata" along with the clade Paenungulata, "Ungulata" has since been determined ...

s, unlike other

South American native ungulate South American native ungulates, commonly abbreviated as SANUs, are extinct ungulate-like mammals that were indigenous to South America from the Paleocene (from at least 63 million years ago) until the end of the Late Pleistocene (~12,000 years a ...

groups, which are often strongly divergent from living ungulates. Paleocene and Eocene litopterns generally had small body masses, with '' Protolipterna'' ( Protolipternidae) estimated to have had a body mass of , though the Eocene

sparnotheriodontids Sparnotheriodontidae is an enigmatic extinct family of litopterns known primarily from teeth. Sparnotheriodontids are one of two South American native ungulate clades known to have reached Antarctica, the other being astrapotheres. Description ...

were considerably larger, with estimated body masses of around . Most proterotheriids had body masses of around while many macraucheniids had body masses of around . Some of the last macraucheniids like ''

Macrauchenia ''Macrauchenia'' ("long llama", based on the now-invalid llama genus, ''Auchenia'', from Greek "big neck") is an extinct genus of large ungulate native to South America from the Pliocene or Middle Pleistocene to the end of the Late Pleistocene. I ...

'' were considerably larger, with body masses around a ton.

Adianthidae Adianthidae is an extinct family of litopterns that existed from the Middle Eocene (Mustersan) to the Early Miocene (Santacrucian). Description Adianthids were actively mobile herbivores. They were small in size when compared to most litopterns ...

generally had small body masses, with members of the genus ''

Adianthus ''Adianthus'' is an extinct genus of litoptern that lived during the Early Miocene to the Middle Miocene in what is now Argentina and Chile. Description This animal is only known from fragmentary remains, mainly from its teeth, and was probably ...

'' estimated to weigh . Members of the proterotheriid subfamily Megadolodinae are noted for having

bunodont The molars or molar teeth are large, flat teeth at the back of the mouth. They are more developed in mammals. They are used primarily to grind food during chewing. The name ''molar'' derives from Latin, ''molaris dens'', meaning "millstone tooth ...

(rounded cusp) molar teeth, which is largely unique to litopterns among South American native ungulates. Litopterns of the mid-late Cenozoic had hinge-like limb joints and

hooves The hoof (: hooves) is the tip of a toe of an ungulate mammal, which is covered and strengthened with a thick and horny keratin covering. Artiodactyls are even-toed ungulates, species whose feet have an even number of digits; the ruminants with ...

similar to those of modern ungulates, with the weight being supported on three toes in macraucheniids and one in proterotheriids, with the protherotheriid ''

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. Macraucheniids had long necks and limbs. Members of the macraucheniid subfamily Macraucheniinae saw the progressive migration of the nasal opening to the top of the skull, which was often historically suggested to indicate the presence of a trunk, though other authors have suggested that a

moose The moose (: 'moose'; used in North America) or elk (: 'elk' or 'elks'; used in Eurasia) (''Alces alces'') is the world's tallest, largest and heaviest extant species of deer and the only species in the genus ''Alces''. It is also the tal ...

-like prehensile lip, or a

saiga The saiga antelope (, ''Saiga tatarica''), or saiga, is a species of antelope which during antiquity inhabited a vast area of the Eurasian steppe, spanning the foothills of the Carpathian Mountains in the northwest and Caucasus in the southwes ...

-like nose to filter dust are more likely.

Ecology

Litopterns were likely

hindgut fermenters Hindgut fermentation is a digestive process seen in monogastric herbivores (animals with a simple, single-chambered stomach). Cellulose is digested with the aid of symbiotic microbes including bacteria, archaea, and eukaryotes. The microbial ferm ...

. At least some macraucheniids like ''Macrauchenia'' are suggested to have been mixed feeders feeding on both browse and grass. Sparnotheriodontids are suggested to have been

browsers Browse, browser, or browsing may refer to: Computing *Browser service, a feature of Microsoft Windows to browse shared network resources *Code browser, a program for navigating source code *File browser or file manager, a program used to manage f ...

. Some proterotheriids are suggested to have been browsers, while some members proterotheriid subfamily Megadolodinae like ''

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 th ...

'' have been suggested to have been

omnivorous An omnivore () is an animal that regularly consumes significant quantities of both plant and animal matter. Obtaining energy and nutrients from plant and animal matter, omnivores digest carbohydrates, protein, fat, and fiber, and metabolize ...

with at least part of their diet consisting of hard fruit.

Evolutionary history

Litopterna, like other "South American native ungulates" is thought to have originated from groups of archaic "

condylarth Condylarthra is an informal group – previously considered an Order (biology), order – of extinct placental mammals, known primarily from the Paleocene and Eocene epochs. They are considered early, primitive ungulates and is now largely consid ...

s" that migrated from North America. Sequencing of the

collagen Collagen () is the main structural protein in the extracellular matrix of the connective tissues of many animals. It is the most abundant protein in mammals, making up 25% to 35% of protein content. Amino acids are bound together to form a trip ...

proteome A proteome is the entire set of proteins that is, or can be, expressed by a genome, cell, tissue, or organism at a certain time. It is the set of expressed proteins in a given type of cell or organism, at a given time, under defined conditions. P ...

and

mitochondrial genome Mitochondrial DNA (mtDNA and mDNA) is the DNA located in the mitochondria organelles in a eukaryotic cell that converts chemical energy from food into adenosine triphosphate (ATP). Mitochondrial DNA is a small portion of the DNA contained in ...

of ''Macrauchenia'' has revealed that litopterns are true ungulates, sharing a common ancestor with

, and with their closest living relatives being

Perissodactyla Perissodactyla (, ), or odd-toed ungulates, is an order of ungulates. The order includes about 17 living species divided into three families: Equidae (horses, asses, and zebras), Rhinocerotidae (rhinoceroses), and Tapiridae (tapirs). They t ...

(the group containing living

equines ''Equus'' () is a genus of mammals in the perissodactyl family (biology), family Equidae, which includes wild horse, horses, Asinus, asses, and zebras. Within the Equidae, ''Equus'' is the only recognized Extant taxon, extant genus, comprising s ...

rhinoceros A rhinoceros ( ; ; ; : rhinoceros or rhinoceroses), commonly abbreviated to rhino, is a member of any of the five extant taxon, extant species (or numerous extinct species) of odd-toed ungulates (perissodactyls) in the family (biology), famil ...

and

tapirs Tapirs ( ) are large, herbivorous mammals belonging to the family Tapiridae. They are similar in shape to a Suidae, pig, with a short, prehensile nose trunk (proboscis). Tapirs inhabit jungle and forest regions of South America, South and Centr ...

) as part of the clade

Panperissodactyla Panperissodactyla ("all perissodactyls", alternatively spelled Pan-Perissodactyla) is a clade of ungulates containing living order Perissodactyla (odd-toed ungulates) and all extinct ungulates more closely related to Perissodactyla than to Artiod ...

, with the split from Perissodactyla being estimated at around 66 million years ago. The relationship of Litopterna to other South American native ungulate groups is uncertain, though it may be closely related to the "condylarth" group

Didolodontidae Didolodontidae is a possibly paraphyletic family of "condylarth" mammals known from the Paleogene of South America, with most specimens known from Argentina. They were generally small-medium in body size, and had a bunodont dentition. A close rel ...

. The earliest litopterns appeared during the early

, around 62.5 million years ago. Aside from South America, sparnotheriodontids are also known from the

aged

La Meseta Formation The La Meseta Formation is a sedimentary sequence deposited during much of the Paleogene on Seymour Island off the coast of the Antarctic Peninsula. It is noted for its fossils, which include both marine organisms and the only terrestrial vertebr ...

in the Antarctic Peninsula, representing the only record of litopterns on the Antarctic continent. Litopterns declined during the

Pliocene The Pliocene ( ; also Pleiocene) is the epoch (geology), epoch in the geologic time scale that extends from 5.33 to 2.58Pleistocene The Pleistocene ( ; referred to colloquially as the ''ice age, Ice Age'') is the geological epoch (geology), epoch that lasted from to 11,700 years ago, spanning the Earth's most recent period of repeated glaciations. Before a change was fin ...

, likely as a result of climatic change and competition with recently immigrated North American ungulates who arrived as part of the

Great American interchange The Great American Biotic Interchange (commonly abbreviated as GABI), also known as the Great American Interchange and the Great American Faunal Interchange, was an important late Cenozoic paleozoogeographic biotic interchange event in which land ...

, following the connection of the previously isolated North and South America via the

Isthmus of Panama The Isthmus of Panama, historically known as the Isthmus of Darien, is the narrow strip of land that lies between the Caribbean Sea and the Pacific Ocean, linking North America, North and South America. The country of Panama is located on the i ...

. ''Macrauchenia,'' ''

Xenorhinotherium ''Xenorhinotherium'' is an extinct genus of macraucheniine macraucheniids, native to northern South America during the Pleistocene and Holocene epoch, closely related to ''Macrauchenia'' of Patagonia. The type species is ''X. bahiense''.

'' (Macraucheniidae) and ''

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 ...

'' (Proterotheriidae) were the last surviving genera of litopterns. All became extinct at the end of the

Late Pleistocene The Late Pleistocene is an unofficial Age (geology), age in the international geologic timescale in chronostratigraphy, also known as the Upper Pleistocene from a Stratigraphy, stratigraphic perspective. It is intended to be the fourth division ...

around 12,000 years ago as part of the end-Pleistocene extinction event, along with most other large mammals in the Americas, co-inciding with the arrival of the first humans to the continent. A study in 2025 suggested that ''Xenorhinotherium'' may have survived until the late Holocene based on a specimen

radiocarbon dated Radiocarbon dating (also referred to as carbon dating or carbon-14 dating) is a method for determining the age of an object containing organic material by using the properties of radiocarbon, a radioactive isotope of carbon. The method was de ...

to 3,493–4,217 years cal.

Before Present Before Present (BP) or "years before present (YBP)" is a time scale used mainly in archaeology, geology, and other scientific disciplines to specify when events occurred relative to the origin of practical radiocarbon dating in the 1950s. Because ...

(BP). It is possible that hunting had a causal role in their extinction.

Classification

* Order Litopterna ** '' Proacrodon'' ** Family Protolipternidae *** '' Asmithwoodwardia'' *** '' Miguelsoria'' *** '' Protolipterna'' ** Family Indaleciidae *** Adiantoides leali

'' Adiantoides'' *** '' Indalecia'' ** Family

Sparnotheriodontidae Sparnotheriodontidae is an enigmatic extinct family of litopterns known primarily from teeth. Sparnotheriodontids are one of two South American native ungulate clades known to have reached Antarctica, the other being astrapotheres. Description ...

*** '' Phoradiadius'' *** ''

Notiolofos ''Notiolofos'' is an extinct genus of Sparnotheriodontidae, sparnotheriodontid ungulate from the order Litopterna. The animal lived during the Eocene, in modern-day Antarctica. The genus contains two species, ''N. arquinotiensis'', the type speci ...

'' *** ''

Sparnotheriodon ''Sparnotheriodon'' is an extinct genus of sparnotheriodontid litoptern that lived during the Middle Eocene of what is now Argentina, leaving fossils in the Sarmiento Formation The Sarmiento Formation (Spanish language, Spanish: ''Formación Sa ...

'' *** ''

Victorlemoinea ''Victorlemoinea'' is an extinct litoptern genus of the family Sparnotheriodontidae, that lived from the Early to Middle Eocene. Fossils of ''Victorlemoinea'' have been found in the Las Flores, Sarmiento and Koluel Kaike Formations of Argentin ...

'' ** Family Amilnedwardsiidae *** ''

Amilnedwardsia ''Amilnedwardsia'' is a genus of extinct ungulates in the family Macraucheniidae Macraucheniidae is a family in the extinct South American ungulate order Litopterna, that resembled camelids. They had three functional digits on the fore and ...

'' *** '' Ernestohaeckelia'' *** '' Rutimeyeria'' ** Family Notonychopidae *** ''

Notonychops ''Notonychops'' is an extinct genus of mammal, belonging to the order Litopterna, that lived during the Middle to Late Paleocene in what is today South America. Description This genus is only known from a fragmentary mandible and maxilla, and ...

'' *** ''

Requisia ''Requisia'' is an extinct genus of litoptern from the Early Paleocene of Argentina. Its fossilized remains were found in the Salamanca Formation in the Chubut Province. It is a monotypic genus, its only known species being ''Requisia vidmari''. ...

'' ** Superfamily

Macrauchenioidea Litopterna (from "smooth heel") is an extinct order of South American native ungulates that lived from the Paleocene to the Pleistocene-Holocene around 62.5 million to 12,000 years ago (or possibly as late as 3,500 years ago), and were also pres ...

*** Family

**** ''

Proectocion ''Proectocion'' is an extinct genus of adianthidae, adianthid litoptern. It lived during the Early Eocene, in what is now South America. Description This genus is mainly known from its fossilized teeth, resembling those of ''Didolodus''. However ...

'' ****

Adianthinae Adianthidae is an extinct family of litopterns that existed from the Middle Eocene (Mustersan) to the Early Miocene (Santacrucian). Description Adianthids were actively mobile herbivores. They were small in size when compared to most litopterns ...

***** ''

'' ***** ''

Proadiantus ''Proadiantus'' (Ameghino, 1897) is an extinct genus of adianthid litoptern. It lived during the Late Oligocene, in what is today South America. It consists of only 1 species, ''Proadiantus excavatus.'' Description This animal is mainly known ...

'' ***** '' Proheptaconus'' ***** ''

Thadanius ''Thadanius'' is an extinct genus of Litoptern, belonging to the family Adianthidae. It lived during the Late Oligocene, in what is today Bolivia. Description Only known from the fossilized remains of its mandible and teeth, this animal may hav ...

'' ***** ''

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 ...

'' *** Family

**** ''

Llullataruca ''Llullataruca'' is an extinct genus of macraucheniid litoptern. It lived during the Middle Miocene of what is now Bolivia. Etymology The genus name, ''Llullataruca,'' is derived from the Quechua words ''llulla'' meaning "false", "lie" or "d ...

'' **** Subfamily Cramaucheniinae ***** ''

Coniopternium ''Coniopternium'' is an extinct genus of macraucheniids from the Late Oligocene of South America. Fossils of ''Coniopternium'' have been found in the Agua de la Piedra, Deseado, and Sarmiento Formations of Argentina, the Salla Formation of Bol ...

'' ***** '' Caliphrium'' ***** ''

Cramauchenia ''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 ge ...

'' ***** '' Phoenixauchenia'' ***** '' Polymorphis'' ***** ''

Pternoconius ''Pternoconius'' is an extinct genus of macraucheniid litoptern from the Late Oligocene and Early Miocene of Argentina. Fossils of this genus have been found in the Sarmiento Formation of Argentina. Etymology The genus name, ''Pternoconius'', ...

'' ***** ''

Theosodon ''Theosodon'' is an extinct genus of litoptern mammal from the Early to Middle Miocene of South America. Description ''Theosodon'' was long-legged with a long neck resembling modern llamas or guanacos. It was large for a litoptern, reachin ...

'' ****

Subfamily In biological classification, a subfamily (Latin: ', plural ') is an auxiliary (intermediate) taxonomic rank, next below family but more inclusive than genus. Standard nomenclature rules end botanical subfamily names with "-oideae", and zo ...

Macraucheniinae Macraucheniidae is a family in the extinct South American ungulate order Litopterna, that resembled camelids. They had three functional digits on the fore and hind feet, as well as elongate necks. The family is generally divided up into two subf ...

***** ''

Cullinia ''Cullinia'' is an extinct genus of litoptern, an order of South American native ungulates that included horse-like and camel-like animals such as ''Macrauchenia''. It is only known from fragmentary remains. ''Cullinia levis'' is known from Chasi ...

'' ***** ''

Huayqueriana ''Huayqueriana'' is an extinct genus of South American litoptern, related to ''Macrauchenia'', and belonging to the same family, Macraucheniidae. It was formerly known as ''Macrauchenidia latidens'', described in 1939 by Cabrera, but redefined as ...

'' ***** ''

Macraucheniopsis ''Macraucheniopsis'' is an extinct genus of litoptern mammal belonging to the family Macraucheniidae from the Middle to Late Pleistocene of Argentina. It, along with ''Macrauchenia'', ''Neolicaphrium'', and ''Xenorhinotherium'' were among the you ...

'' ***** '' Oxyodontherium'' ***** ''

Paranauchenia ''Paranauchenia'' is an extinct genus of South American litopterns belonging to the family Macraucheniidae. It is known only from fossil finds in Argentina. It possessed three toes and long limbs. The species ''Paranauchenia denticulata'' lived i ...

'' ***** ''

Promacrauchenia ''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'', ''Macra ...

'' ***** ''

Scalabrinitherium ''Scalabrinitherium'' is an extinct genus of mammals of the family Macraucheniidae. Fossils of this animal were found among the fossils of prehistoric xenarthrans in the Ituzaingó Formation of Argentina.Windhausenia ''Windhausenia'' is an extinct genus of mammals belonging to the family Macraucheniidae and the order Litopterna. While it reached the size of its better known relative ''Macrauchenia'', its constitution was lighter. Remains from the genus have b ...

'' ***** ''

'' ** Superfamily Proterotherioidea *** Family

****

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 ...

'' **** ''

Eoauchenia ''Eoauchenia'' is a genus of extinct 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 Pliocene Monte H ...

'' **** '' 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 Arg ...

'' **** ''

Guilielmofloweria ''Guilielmofloweria'' is an extinct genus of proterotheriidae, proterotheriid litopterna, 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 ' ...

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

Lambdaconus ''Lambdaconus'' is a genus of proterotheriidae, proterotheriid from the Oligocene, 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 a ...

'' **** '' 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 ...

'' **** ''

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 Proterotheriidae, proterotheriid litopterns from the Early Miocene of what is now Argentina and Chile. Its fossils have been found in the Sarmiento Formation, Sarmiento and Santa Cruz Formation, Argentin ...

'' **** '' Paranisolambda'' **** ''

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 ...

'' **** '' Promylophis'' **** ''

Proterotherium ''Proterotherium'' (meaning "first beast") is an extinct genus of litoptern mammal of the family Proterotheriidae that lived during the Late Miocene of Argentina Argentina, officially the Argentine Republic, is a country in the southern ...

'' **** ''

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 lowe ...

'' **** ''

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 pelite ...

'' **** ''

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 ...

'' **** ''

Uruguayodon ''Uruguayodon'' is an extinct genus of proterotheriid from the middle Pleistocene of Uruguay. It is known from the type and only species ''U. alius'', named by Corona and colleagues in 2019 for dentaries and a partial postcrania from the Raigón ...

'' **** ''

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 ''Xesmodon'' is an extinct genus of mammal. It lived from the Middle to the Late Eocene, in what is today South America. Taxonomy ''Xesmodon'' was named by Carlos Berg in 1899. Its type species is ''Xesmodon langi'', and a second species, ''Xes ...

'' **** 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, AMU-C ...

'' ***** ''

References

External links

An artist's rendition
of a

, a representative genus of the Litopterna. Retrieved from the

Red Académica Uruguaya The University of the Republic (, sometimes ''UdelaR'') is a public research university in Montevideo, Uruguay. It is the country's oldest and largest university, as well as one of the largest public universities in South America in terms of en ...

br>megafauna page
{{Taxonbar, from=Q132153 Panperissodactyla Danian first appearances Holocene extinctions Fossil taxa described in 1889 Taxa named by Florentino Ameghino

Diversity

Ecology

Evolutionary history

Classification

References

Further reading

External links