Parent taxon: Caviomorpha according to M. Boivin et al. 2017
See also Carroll 1988, Nowak 1999, Wood 1958 and Wood and Patterson 1959
Sister taxa: Aenigmys, Balsayacuy, Cachiyacuy, Canaanimys, Cavioidea, Cephalomyidae, Chachapoyamys, Chambiramys, Chinchillidae, Chinchilloidea, Luribayomys, Luribayomys masticator, Octodontoidea, Palmiramys, Palmiramys waltheri, Pozomys, Tacheria, Tarapotomys, Vucetichimys, Zetamyidae
Subtaxa: Eosteiromys Erethizontidae Kichkasteiromys Nuyuyomys Plesiosteiromys Shapajamys Steiromys
Ecology: ground dwelling herbivore
Distribution:
• Quaternary of Argentina (1 collection), Bolivia (2), Brazil (6), Canada (4: Alberta, Ontario, Quebec), Mexico (2), Panama (1), Peru (1), United States (58: Alaska, Arkansas, California, Colorado, Florida, Idaho, Maryland, Missouri, Nebraska, New Mexico, Ohio, Pennsylvania, South Carolina, Tennessee, Texas, Utah, Virginia, West Virginia), Uruguay (2), Venezuela (1)
• Blancan of United States (9: Arizona, California, Florida, Idaho)
• Pliocene to Pleistocene of Venezuela (1)
• Pliocene of Argentina (1), Colombia (1)
• Huayquerian of Argentina (1), Bolivia (1)
• Miocene of Argentina (29), Brazil (5), Chile (1), Colombia (6), Peru (3)
• Deseadan of Argentina (2), Bolivia (2)
• Oligocene of Colombia (1), Peru (6)
Total: 147 collections including 200 occurrences