''Eopachyrucos'' is an extinct genus of interatheriid

notoungulates 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 ...

that lived from the Middle Eocene to the Late Oligocene of

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 ...

and

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 ...

. Fossils of this genus have been found in the

Sarmiento Formation The Sarmiento Formation (Spanish language, 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 y ...

of Argentina and the

Fray Bentos Formation The Fray Bentos Formation is a Deseadan geologic formation of the Paysandú Group in Uruguay and portions of Argentina, corresponding to the Paraná Basin.Bond et al., 1998, p.42Tófalo & Morrás, 2009, p.680 It is composed of calcareous sandst ...

of Uruguay.

Taxonomy

''Eopachyrucos'' was first named in 1901 by Florentino Ameghino based on fragmentary remains found in the Sarmiento Formation of Argentina. He originally considered it as a member of the family

Hegetotheriidae Hegetotheriidae is an extinct family of notoungulate mammals known from the Oligocene through the Pliocene of South America South America is a continent entirely in the Western Hemisphere and mostly in the Southern Hemisphere, with a c ...

, as an ancestor of ''

Pachyrukhos ''Pachyrukhos'' is an extinct genus of hegetotheriid notoungulate from the Early to Middle Miocene ( Colhuehuapian- Friasian in the SALMA classification) of Argentina and Chile. Fossils of this genus have been found in the Collón Curá, Sarm ...

'', as reflected in its name ("dawn ''Pachyrukhos''"), however, recent studies have confirmed it to be a member of the family

Interatheriidae Interatheriidae is an extinct family of notoungulate mammals from South America. Interatheriids are known from the Middle Eocene (Mustersan) to the Early Pleistocene (Uquian).McKenna & Bell, 1997Linares, 2004 These animals were principally small- ...

, more specifically within the subfamily Interatheriinae. The following cladogram of the

Interatheriinae Interatheriinae is an extinct subfamily of interatheriids that consisted of notoungulates dating from the Early Eocene (Casamayoran SALMA) to the Early Pliocene (Montehermosan SALMA). The subfamily includes the genera '' Archaeophylus'', '' Argy ...

is based on Vera ''et al.'' 2017, showing the position of ''Eopachyrucos''.

References

{{Taxonbar, from=Q113638577 Typotheres Prehistoric placental genera Oligocene mammals of South America Eocene mammals of South America Deseadan Tinguirirican Divisaderan Mustersan Paleogene Argentina Oligocene Uruguay Fossils of Argentina Fossils of Uruguay Taxa named by Florentino Ameghino Fossil taxa described in 1901 Golfo San Jorge Basin Sarmiento Formation Fray Bentos Formation