Scapteromys

Scapteromys is a genus of South American rodents in the tribe Akodontini of family Cricetidae. Three species are known, found in northern Argentina, southern Brazil, Paraguay and Uruguay.^[1][2] They are as follows:

• Argentine swamp rat (Scapteromys aquaticus)
• Plateau swamp rat (Scapteromys meridionalis)
• Waterhouse's swamp rat (Scapteromys tumidus)

Scapteromys Temporal range: Late Pliocene to Recent
Scientific classification
Kingdom:	Animalia
Phylum:	Chordata
Class:	Mammalia
Order:	Rodentia
Family:	Cricetidae
Subfamily:	Sigmodontinae
Tribe:	Akodontini
Genus:	Scapteromys Waterhouse, 1837
Type species
Mus tumidus Waterhouse, 1837
Species
Scapteromys aquaticus Scapteromys meridionalis Scapteromys tumidus

Species are semiaquatic, living in and near marshes and other bodies of water. They reach a body length of 15 to 20 cm and a tail length of 13–17 cm, and weigh 110-200 g. Fur color is dark gray on top and light gray on the underside. They are primarily crepuscular and nocturnal. Their diet consists mainly of insects; they also consume other invertebrates and plant material.

The three species differ in karyotype, with aquaticus having 2n = 32, tumidus 2n = 24^[1] and meridionalis 2n = 34/36.^[2]