Scapteromys

{{Short description|Genus of rodents}}

{{automatic taxobox

| fossil_range = Late Pliocene to Recent

| taxon = Scapteromys

| authority = Waterhouse, 1837

| type_species = Mus tumidus

| type_species_authority = Waterhouse, 1837

| subdivision_ranks = Species

| subdivision =

Scapteromys aquaticus

Scapteromys meridionalis

Scapteromys tumidus

}}

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.{{MSW3 Muroidea | id = 13000903 | page = 1172}}{{cite journal |author1=Quintela, F.M. |author2=Goncalves, G.L. |author3=Althoff, S.L. |author4=Sbalqueiro, I.J. |author5=Oliveira, L.F.B. |author6=de Freitas, T.R.O. |year=2014 |title=A new species of swamp rat of the genus Scapteromys Waterhouse, 1837 (Rodentia: Sigmodontinae) endemic to Araucaria angustifolia forest in southern Brazil |journal=Zootaxa |volume=3811 |issue=2 |pages=207–225 |doi=10.11646/zootaxa.3811.2.3|pmid=24943159 }} They are as follows:

• Argentine swamp rat (Scapteromys aquaticus)
• Plateau swamp rat (Scapteromys meridionalis)
• Waterhouse's swamp rat (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 and meridionalis 2n = 34/36.