Scapteromys fossil map
Where fossils of Scapteromys have been found, shown on the Earth as it looked about 0 million years ago and on today’s map.
Dots are fossil collections recorded in the Paleobiology Database. The “then” view moves today’s fossil sites back to their positions 0 million years ago (the time slice nearest the median age of the fossils) using the Merdith et al. (2021) plate model; positions are approximate. Open on the timeline map →
| Group | Early mammals |
|---|---|
| Lived | 3.8 million years ago to the present (Zanclean to Holocene) |
| Periods | Neogene, Quaternary |
| Family | Cricetidae |
| Named by | Waterhouse 1837 |
| Fossil records | 8 occurrences at 4 locations (PBDB) |
| Found in | Brazil, Argentina |
| Rock formations | txn:41724, Botucatu, San Andres |
About 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. 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.
Text in “About” is quoted from the Wikipedia article Scapteromys (revision 1325885780), licensed under CC BY-SA 4.0; introduction excerpted verbatim, formatting removed. Ages, family, authority and fossil records: Paleobiology Database, accessed 23 October 2026. Ages are those of the rock layers the fossils were found in. Wikidata: Q139896.
