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 crab-eating fox, also known as the forest fox, wood fox, bushdog or maikong, is an extant species of medium-sized canid endemic to the central part of South America since at least the Pleistocene epoch. Like South American foxes, which are in the genus Lycalopex, it is not closely related to true foxes. Cerdocyon comes from the Greek words kerdo and kyon (dog) referring to the dog- and fox-like characteristics of this animal.
The crab-eating mongoose is a species of mongoose found from the north-eastern Indian subcontinent and Southeast Asia to southern China and Taiwan. It is listed as Least Concern on the IUCN Red List.
The squirrel-toothed rat, also known as the New Guinea giant rat, powerful-toothed rat, uneven-toothed rat, or narrow-toothed giant rat, is a species of rodent in the family Muridae. It is the only species in the genus Anisomys and is found in New Guinea.
The aquatic rat, Ecuador fish-eating rat, fish-eating rat or Ecuadoran ichthyomyine is a South American species of semiaquatic rodent in the family Cricetidae. It is the only species in the genus Anotomys. This species is currently considered endangered. It is thought to be nocturnal and feeds on aquatic arthropods and insects. It is found in small ranges along the Andes.
The crab-eating rat is a species of semiaquatic rodent in the family Cricetidae. It is found in Colombia, Ecuador, and Venezuela. Its natural habitats are rivers and swamps.
Pittier's crab-eating rat is a species of semiaquatic rodent in the family Cricetidae. It is endemic to Venezuela. The natural habitats of this species are rivers and swamps. Its karyotype has 2n = 92 and FNa = 98. This was previously thought to be the highest chromosome number known for a mammal, but it has since been found that the plains viscacha rat or red viscacha rat has 4x = 2n = 102.
Stolzmann's crab-eating rat is a species of rodent in the family Cricetidae. It is found in Ecuador and Peru. The species is believed to be nocturnal and semiaquatic, and has been found at an elevation range of 900 to 1700 m. A survey in 2010 indicates that it is becoming a nuisance at local trout farms in the Peruvian puna.
Tweedy's crab-eating rat is a species of rodent in the family Cricetidae. It is found in two disjointed regions in western Ecuador and central Panama. The species is found near fast-flowing streams in primary and secondary forest, and is known from elevations of 900 to 1700 m. It is presumed that like other members of its genus, it nocturnal and semiaquatic, and feeds on freshwater invertebrates, such as crabs. This rodent is threatened by habitat destruction and water pollution.
The Indian gerbil also known as antelope rat, is a species of rodent in the family Muridae.
The Christmas Island shrew, also known as the Christmas Island musk-shrew is an extremely rare or possibly extinct shrew from Christmas Island. It was variously placed as subspecies of the Asian gray shrew or the Southeast Asian shrew, but morphological differences and the large distance between the species indicate that it is an entirely distinct species.
