The rodent subfamily Sigmodontinae includes New World rats and mice, with at least 376 species. Many authorities include the Neotominae and Tylomyinae as part of a larger definition of Sigmodontinae. When those genera are included, the species count numbers at least 508. Their distribution includes much of the New World, but the genera are predominantly South American, such as brucies. They invaded South America from Central America as part of the Great American Interchange near the end of the Miocene, about 5 million years ago. Sigmodontines proceeded to diversify explosively in the formerly isolated continent. They inhabit many of the same ecological niches that the Murinae occupy in the Old World.
The genus Eligmodontia consists of five or six species of South American sigmodontine mice restricted to Bolivia, Chile, and Argentina. Species of Eligmodontia occur along the eastern side of the Andes Mountains, in Patagonia, and in the Chaco thorn forest of South America. They can be found in arid and semiarid habitats and in both high and low elevation areas. These rodents are commonly known as gerbil mice or by their local name lauchas. Sometimes they are also called silky desert mice, highland desert mice or silky-footed mice. The closest living relatives are probably the chaco mice (Andalgalomys), the leaf-eared mice, and Salinomys.
The gray leaf-eared mouse is a rodent species from South America. It is found in Argentina, Bolivia, Brazil and Paraguay; its habitat includes the Gran Chaco.
The pale leaf-eared mouse is a species of rodent in the family Cricetidae. It is found in Argentina and Bolivia.
Edith's leaf-eared mouse is a species of rodentin the family Cricetidae. It is known only from Argentina, where it was found in a montane grassland on Otro Cerro at an elevation of 3000 m.
Phyllotis is a genus of rodent in the family Cricetidae. These mice are commonly confused with Auliscomys, Graomys and Loxodontomys.. In order to tell these genera apart, one must look at the tail. Species in the genus Phyllotis have a penicillate tip on their tail which is not present in the other two genera. Tails in the genus Phyllotis are also less than the length of its head and body combined whereas in Graomys, tails are longer than the head and body combined. Phyllotis xanthopygus was found at the summit of Volcán Llullaillaco, which is the highest altitude a mammal has yet been found in nature.
The yellow-rumped leaf-eared mouse, otherwise known as the Patagonian leaf-eared mouse, is a species of rodent in the family Cricetidae and order Rodentia. It is the most widespread member of the genus.
Hassalstrongylus is a genus of nematode worms that infect mostly muroid rodents from eastern North America to South America. The genus is part of the Heligmonellidae and related to genera like Stilestrongylus.
