Baiomys fossil map
Where fossils of Baiomys have been found, shown on the Earth as it looked about 5 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 5 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 | 9.4–0.21 million years ago (Tortonian to Chibanian) |
| Periods | Neogene, Quaternary |
| Family | Cricetidae |
| Named by | True 1894 |
| Fossil records | 70 occurrences at 19 locations (PBDB) |
| Found in | United States, Mexico |
| Rock formations | txn:41724, St. David, Gila Conglomerate, Rexroad, Glenns Ferry, San Timoteo |
About Baiomys
Baiomys, the New World pygmy mice, is a genus of rodents in the family Cricetidae. Together with Scotinomys, it forms the tribe Baiomyini. It contains the smallest rodents in North America. It currently contains three extant species:
Southern pygmy mouse, Baiomys brunneus
Mexican pygmy mouse, Baiomys musculus
Northern pygmy mouse, Baiomys taylori
Additionally, there are seven known fossil species:
Baiomys aquilonius Zakrzewski, 1969
Baiomys brachygnathus (Gidley, 1922)
Baiomys intermedius Packard & T. Alvarez, 1965
Baiomys kolbi Hibbard, 1952
Baiomys minimus (Gidley, 1922)
Baiomys rexroadi Hibbard, 1941
Baiomys sawrockensis Hibbard, 1953
Text in “About” is quoted from the Wikipedia article Baiomys (revision 1379510431), 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: Q469583.
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