''Sparnotheriodon'' is an extinct genus of sparnotheriodontid

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 ...

that lived during the Middle Eocene of what is now

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 ...

, leaving fossils in the

Sarmiento Formation The Sarmiento Formation (Spanish: ''Formación Sarmiento''), in older literature described as the Casamayor Formation, is a geological formation in Chubut Province, Argentina, in central Patagonia, which spans around 30 million years from the mid- ...

Description

''Sparnotheriodon'' was a medium-sized litoptern. ''Sparnotheriodon'', ''

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 Argenti ...

'', and one species of ''Notiolofos'', ''N. arquinotiensis'', have been estimated to have had masses of roughly , whereas another species of ''Notiolofos'', ''N. regueroi'', was smaller, with a body mass estimated between 25 and 58 kg, making them one of the largest litopterns of the Paleogene. Litopterns reached such sizes again in the Miocene.

Taxonomy

''Sparnotheriodon'' was first named by Miguel Fernando Soria in 1980 on the basis of a mandible and teeth from the Sarmiento Formation of Argentina, with the type species being ''Sparnotheriodon epsilonoides''. In 1983,

Richard Cifelli Richard is a male given name. It originates, via Old French, from Old Frankish and is a compound of the words descending from Proto-Germanic ''*rīk-'' 'ruler, leader, king' and ''*hardu-'' 'strong, brave, hardy', and it therefore means 'stron ...

tentatively synonymized ''Sparnotheriodon'' with ''

''. Other authors consider it distinct.

References

{{Taxonbar, from=Q113681958 Sparnotheriodontids Eocene mammals of South America Prehistoric placental genera Mustersan Paleogene Argentina Fossils of Argentina Fossil taxa described in 1980 Golfo San Jorge Basin Sarmiento Formation