''Perimys'' is an extinct genus of neoepiblemid

rodent Rodents (from Latin , 'to gnaw') are mammals of the Order (biology), order Rodentia (), which are characterized by a single pair of continuously growing incisors in each of the upper and lower jaws. About 40% of all mammal species are roden ...

that lived from the Early to Late Miocene in what is now

South America South America is a continent entirely in the Western Hemisphere and mostly in the Southern Hemisphere, with a relatively small portion in the Northern Hemisphere at the northern tip of the continent. It can also be described as the souther ...

. Fossils have been found in the Cerro Bandera, Cerro Boleadoras, CC-BY_icon

Material was copied from this source, which is available under a Creative Commons Attribution 3.0 International License Ituzaingó, Santa Cruz, and

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- ...

s of

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, t ...

, and the Galera, Santa Cruz and

Río Frías Formation Río Frías Formation ( es, Formación Río Frías) is a Middle Miocene geologic formation made up sedimentary rock located in Aysén Region, western Patagonia. The formation crops out along the upper couse of Cisnes River ( es, Río Cisnes).Mars ...

s of

Chile Chile, officially the Republic of Chile, is a country in the western part of South America. It is the southernmost country in the world, and the closest to Antarctica, occupying a long and narrow strip of land between the Andes to the eas ...

Description

''Perimys'' was a medium to large-sized rodent. ''Perimys'' can be distinguished from other caviomorphs in having euhypsodont and bilophodont cheek teeth, with the hypoflexus/id being conspicuously broader and filled with more

cementum Cementum is a specialized calcified substance covering the root of a tooth. The cementum is the part of the periodontium that attaches the teeth to the alveolar bone by anchoring the periodontal ligament.Illustrated Dental Embryology, Histology, ...

than in '' Prolagostomus'' and '' Pliolagostomus''. As a result, the teeth of ''Perimys'' have a U-shape occlusal outline.

Taxonomy

''Perimys'' was first described by Florentino Ameghino in 1887 based on remains found in the Santa Cruz Formation of Argentina, with the proposed type species being ''Perimys erutus''. Several other species have been described as pertaining to this genus. Ameghino originally assigned it to the obsolete family Eryomyidae, however, many later authors have assigned it to the

Neoepiblemidae The Neoepiblemidae are an extinct family of hystricognath rodents from South America. The genera '' Dabbenea'' and '' Perumys'' are now included in ''Phoberomys''. The delineation between Neoepiblemidae and Dinomyidae has historically been uncl ...

family. The following cladogram of the

Caviomorpha Caviomorpha is the rodent infraorder or parvorder that unites all New World hystricognaths. It is supported by both fossil and molecular evidence. The Caviomorpha was for a time considered to be a separate order outside the Rodentia, but is now a ...

is based on Busker ''et al.'' 2020, showing the position of ''Perimys''.

References

{{taxonbar, from=Q114348803 Hystricognath rodents Miocene rodents Miocene mammals of South America Colhuehuapian Santacrucian Friasian Colloncuran Laventan Mayoan Chasicoan Huayquerian Neogene Argentina Fossils of Argentina Fossil taxa described in 1887 Prehistoric rodent genera Austral or Magallanes Basin Golfo San Jorge Basin Neuquén Basin Paraná Basin Santa Cruz Formation Sarmiento Formation Cerro Bandera Formation Ituzaingó Formation