Perimys

Perimys is an extinct genus of neoepiblemid rodent that lived from the Early to Late Miocene in what is now South America. Fossils have been found in the Cerro Bandera,^[1] Cerro Boleadoras,^[2] Ituzaingó, Santa Cruz,^[3] and Sarmiento Formations of Argentina,^[4] and the Galera,^[5] Santa Cruz^[6] and Río Frías Formations of Chile.

Perimys Temporal range: Early-Late Miocene (Colhuehuapian-Huayquerian) ~21.0–6.8 Ma PreꞒ Ꞓ O S D C P T J K Pg N
Left m1 and m2 of Perimys sp.
Scientific classification
Domain:	Eukaryota
Kingdom:	Animalia
Phylum:	Chordata
Class:	Mammalia
Order:	Rodentia
Family:	†Neoepiblemidae
Genus:	†Perimys Ameghino, 1887
Type species
†Perimys erutus Ameghino, 1887
Species
P. ameghinoi Scott 1905 P. dissimilis Ameghino 1902 P. erutus Ameghino 1887 P. impactus Ameghino 1894 P. incavatus Ameghino 1902 P. incurvus Ameghino 1902 P. intermedius Kramarz 2002 P. oemulus Ameghino 1894 P. onustus Ameghino 1887 P. pacificus Ameghino 1894 P. perpinguis Ameghino 1891 P. planaris Ameghino 1891 P. puellus Ameghino 1891 P. pueraster Ameghino 1891 P. scalabrinianus Ameghino 1889 P. transversus Ameghino 1902
Synonyms
Sphodromys Ameghino 1887

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 than in Prolagostomus and Pliolagostomus. As a result, the teeth of Perimys have a U-shape occlusal outline.^[2]

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,^[7] however, many later authors have assigned it to the Neoepiblemidae family.^[8][9]

The following cladogram of the Caviomorpha is based on Busker et al. 2020, showing the position of Perimys.^[8]

Baluchimyinae Bugtimys zafarullahi "Phiomorpha" Phiomys andrewsi Metaphiomys schaubi Octodontoidea Prospaniomys priscus Myocastor coypus Echimyidae Proechimys polioplus Eumysops laeviplicatus Kannabateomys amblyonyx Echimys chrysurus Ctenomyidae Ctenomys australis Plataeomys brevis Pithanotomys columnaris Octomys mimax Octodontomys gliroides Chasichimys bonaerense Chasicomys octodontiforme Acarechimys leucotheae Acarechimys minutus Acaremyidae Acaremys murinus Galileomys antelucanus Galileomys baios Erethizontoidea Steiromys detentus Eosteiromys homogenidens Dasyproctidae Dasyprocta azarae Node A Eoviscaccia frassinettii Eoviscaccia boliviana Garridomys curunuquem Incamys bolivianus Asteromys bolivianus Asteromys punctus Cephalomyidae Cephalomys ceciae Cephalomyopsis hypselodontus Litodontomys chubutensis Cephalomys arcidens Scotamys antiquus Neoepiblemidae Perimys intermedius Chinchillidae Lagostomus maximus Lagidium viscacia Chinchilla chinchilla Node B Banderomys leanzai Soriamys ganganensis Soriamys gaimanensis Luantus propheticus Guiomys unica Microcavia australis Cavia aperea Galea musteloides Dolichotis patagonum

References

1. Kramarz, Alejandro; Garrido, Alberto; Forasiepi, Analía; Bond, Mariano; Tambussi, Claudia (2005). "Stratigraphy and vertebrates (Aves and Mammalia) from the Cerro Bandera Formation, Early Miocene of Neuquén Province, Argentina". Revista Geológica de Chile. 32 (2). doi:10.4067/S0716-02082005000200006.
2. Vizcaino, Sergio F.; Bargo, M. Susana; Pérez, M. Encarnación; Aramendía, Inés; Cuitiño, José I.; Monsalvo, Eduardo S.; Vlachos, Evangelos; Noriega, Jorge I.; Kay, Richard F. (2022-09-30). "Fossil vertebrates of the early-middle Miocene Cerro Boleadoras Formation, northwestern Santa Cruz Province, Patagonia, Argentina". Andean Geology. 49 (3): 382–422. doi:10.5027/andgeoV49n3-3425. ISSN 0718-7106. Material was copied from this source, which is available under a Creative Commons Attribution 3.0 International License
3. Kramarz, Alejandro (2014-06-08). "Roedores chinchilloideos (Hystricognathi) de la Formación Pinturas, Mioceno temprano-medio de la provincia de Santa Cruz, Argentina". Revista del Museo Argentino de Ciencias Naturales. Nueva Serie. 4 (2): 167–180. ISSN 1853-0400.
4. Madden, Richard H.; Carlini, Alfredo A.; Vucetich, Maria Guiomar; Kay, Richard F. (2010-06-17). "Colhuehuapian rodents from Gran Barranca and other Patagonian localities: the state of the art.". The Paleontology of Gran Barranca: Evolution and Environmental Change Through the Middle Cenozoic of Patagonia. Cambridge University Press. ISBN 978-0-521-87241-6.
5. McGrath, Andrew J.; Chick, Jennifer; Croft, Darin A.; Dodson, Holly E.; Flynn, John J.; Wyss, André R. (2022-02-08). "Cavioids, Chinchilloids, and Erethizontoids (Hystricognathi, Rodentia, Mammalia) of the Early Miocene Pampa Castillo Fauna, Chile". American Museum Novitates (3984): 1–46. doi:10.1206/3984.1. ISSN 0003-0082.
6. Bostelmann, J. Enrique; Roux, Jacobous P. Le; Vásquez, Ana; Gutiérrez, Néstor M.; Oyarzún, José Luis; Carreño, Catalina; Torres, Teresa; Otero, Rodrigo; Llanos, Andrea; Fanning, C. Mark; Hervé, Francisco (2013-07-25). "Burdigalian deposits of the Santa Cruz Formation in the Sierra Baguales, Austral (Magallanes) Basin: Age, depositional environment and vertebrate fossils". Andean Geology. 40 (3): 458–489. doi:10.5027/andgeoV40n3-a04. hdl:10533/138811. ISSN 0718-7106.
7. Ameghino, Florentino (1891). "Nuevos restos de mamíferos fósiles descubiertos por Carlos Ameghino en el Eoceno inferior de la Patagonia austral. — Especies nuevas, adiciones y correcciones". Revista argentina de historia natural. 1: 289–328.
8. Busker, Felipe; Dozo, María Teresa; Soto, Ignacio María (2020-10-01). "New remains of Cephalomys arcidens (Rodentia, Caviomorpha) and a redefinition of the enigmatic Cephalomyidae". Journal of Systematic Palaeontology. 18 (19): 1589–1629. Bibcode:2020JSPal..18.1589B. doi:10.1080/14772019.2020.1796833. ISSN 1477-2019. S2CID 225308634.
9. Vucetich, María Guiomar (1989). "Rodents (Mammalia) of the Lacayani fauna revisited (Deseadan, Bolivia). Comparison with new Chinchillidae and Cephalomyidae from Argentina". Bulletin du Muséum national d'histoire naturelle. 11 (4): 233–247.