''Uruguayodon'' is an extinct

genus Genus (; : genera ) is a taxonomic rank above species and below family (taxonomy), family as used in the biological classification of extant taxon, living and fossil organisms as well as Virus classification#ICTV classification, viruses. In bino ...

of proterotheriid from the middle

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 ...

Uruguay Uruguay, officially the Oriental Republic of Uruguay, is a country in South America. It shares borders with Argentina to its west and southwest and Brazil to its north and northeast, while bordering the Río de la Plata to the south and the A ...

. 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 Formation The Raigón Formation is a geologic formation in Uruguay dated between the Pliocene and Middle Pleistocene. Overview In 1966, Uruguayan geologists Héctor Goso and Jorge Bossi defined the Raigón Formation, which they subdivided into the San ...

. ''Uruguayodon'' represents one of the latest occurrences of Proterotheriidae, with only ''

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 ...

'' representing other remains from the

to possibly

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 ...

Description

This animal would have been very similar to other proterotheriids, such as ''

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 ...

'' or ''

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 ...

''. ''Uruguayodon'' possessed slender and elongated legs, equipped with three toes (the middle one of which was well developed). The skull was equipped with a rather short and high snout, with fairly elongated nasal bones. The molar had closely spaced internal tubercles but, in contrast to ''Anisolophus,'' the last lower molar was characterized by paraconid and paralophid in a lingually peripheral position; the metaflexis was smooth and there was no entoflexis.

Classification

''Uruguayodon'' was described in 2019, based on fossil remains found in

, in the San José member of the

. Another mammal has been found in the formation, ''

Charruatoxodon ''Charruatoxodon'' is an extinct monotypic genus of notoungulate belonging to the family Toxodontidae. It lived from the Pliocene to the Early Pleistocene in what is now southern Uruguay. Its remains have been found in the San José member of th ...

'', a toxodontid

notoungulate 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 ...

described in 2022. The fossils of ''Uruguayodon'' had previously been ascribed to the genus ''Anisolophus'', but a redescription allowed them to be attributed to a new genus and species. ''Uruguayodon'' is a derived member of the Proterotheriidae, a group of litoptern mammals, which during the Cenozoic developed

evolutionary convergence Convergent evolution is the independent evolution of similar features in species of different periods or epochs in time. Convergent evolution creates analogous structures that have similar form or function but were not present in the last comm ...

with the equids, particularly with regards to their legs. ''Uruguayodon'' is the second known proterotheriid known from the Pleistocene, after ''

''. Below is a phylogenetic tree of the Proterotheriidae, based on the work of McGrath ''et al''. 2020, showing the position of ''Uruguayodon''.

References

{{Taxonbar, from=Q111828147 Proterotheriids Pleistocene mammals of South America Pleistocene Uruguay Fossils of Uruguay Ensenadan Fossil taxa described in 2019 Prehistoric placental genera