''Thoatherium'' (meaning "active swift-beast") is an extinct genus of litoptern mammals from the

Early Miocene The Early Miocene (also known as Lower Miocene) is a sub-epoch of the Miocene epoch (geology), Epoch made up of two faunal stage, stages: the Aquitanian age, Aquitanian and Burdigalian stages. The sub-epoch lasted from 23.03 ± 0.05 annum, Ma to ...

Argentina Argentina, officially the Argentine Republic, is a country in the southern half of South America. It covers an area of , making it the List of South American countries by area, second-largest country in South America after Brazil, the fourt ...

. Fossils of the genus have been found in the

Santa Cruz Formation The Santa Cruz Formation is a geological formation in the Magallanes Basin, Magallanes/Austral Basin in southern Patagonia in Argentina and adjacent areas of Chile. It dates to the late Early Miocene epoch, and is contemporaneous with the eponym ...

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Fossilworks Fossilworks was a portal which provides query, download, and analysis tools to facilitate access to the Paleobiology Database, a large relational database assembled by hundreds of paleontologists from around the world. History Fossilworks was cr ...

.org

Description

With a length of , the

gazelle A gazelle is one of many antelope species in the genus ''Gazella'' . There are also seven species included in two further genera; '' Eudorcas'' and '' Nanger'', which were formerly considered subgenera of ''Gazella''. A third former subgenus, ' ...

-like ''Thoatherium'' was a small representative of the order

Litopterna Litopterna (from "smooth heel") is an extinction, 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 we ...

. Judging from its long legs, it was a fast runner. ''Thoatherium'' had remarkably reduced toes; only one

horse 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 mi ...

-like

hoof 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 ...

remained. ''Thoatherium'' even lacked splint bones, which are remnants of the second and fourth toe found in modern horses. Judging from its generalised, brachydont teeth, ''Thoatherium'' fed on soft leaves rather than on tough grasses.Darin A. Croft, ''Horned Armadillos and Rafting Monkeys: The Fascinating Fossil Mammals of South America'', Indiana University Press, 29/08/2016

References

Proterotheriids Burdigalian life Miocene mammals of South America Santacrucian Neogene Argentina Fossils of Argentina Fossil taxa described in 1887 Taxa named by Florentino Ameghino Prehistoric placental genera {{paleo-mammal-stub