Stygimys fossil map
Where fossils of Stygimys have been found, shown on the Earth as it looked about 66 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 66 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 | 83.6–60.9 million years ago (Campanian to Selandian) |
| Periods | Cretaceous, Paleogene |
| Family | Eucosmodontidae |
| Named by | Sloan and Van Valen 1965 |
| Fossil records | 156 occurrences at 14 locations (PBDB) |
| Found in | United States, Canada, Mexico |
| Rock formations | Hell Creek, Fort Union, Ravenscrag, "Fort Union" (= Lebo), Porcupine Hills, El Gallo |
About Stygimys
Stygimys is an extinct mammal genus from the Upper Cretaceous and Paleocene of North America and Russia. It was a member of the extinct order Multituberculata within the suborder Cimolodonta, family Eucosmodontidae.
The genus Stygimys ("Styx mouse") was named by R.E. Sloan and Leigh Van Valen in 1965. The name comes from the Styx (river of hell) from Greek mythology. The genus has also been known as Catopsalis (partly); Cimexomys (partly); Eucosmodon (partly); and Parectypodus (partly). Some skull material is known, but not much.
Text in “About” is quoted from the Wikipedia article Stygimys (revision 1376551235), 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: Q7629326.
