Armintomys

{{Short description|Extinct genus of rodents}}

{{Speciesbox

| fossil_range = {{geological range|50.3|46.2}}

| grandparent_authority = Dawson, Krishtalka, & Stucky, 1990

| parent_authority = Dawson, Krishtalka, & Stucky, 1990

| taxon = Armintomys tullbergi

| authority = Dawson, Krishtalka, & Stucky, 1990

| display_parents = 3

}}

Armintomys is an extinct genus of rodent from North America related to jerboas and jumping mice. It is the only genus in the family Armintomyidae. It lived during the early Eocene, and is the oldest known example of a hystricomorphous zygomasseteric dentition.{{cite journal |last1=Dawson |first1=Mary R. |last2=Krishtalka |first2=Leonard |last3=Stucky |first3=Richard K. |title=Revision of the Wind River faunas, early Eocene of central Wyoming. IX - The oldest known hystricomorphous rodent (Mammalia: Rodentia) |journal=Carnegie Museum of Natural History, Annals |date=June 8, 1990 |volume=59 |issue=2 |url=https://ntrs.nasa.gov/citations/19930060906 |access-date=3 March 2021 |publisher=NASA |doi=10.5962/p.240768 |issn=0097-4463|doi-access=free }} In addition, Armintomys is also the oldest known rodent that had an incisor enamel transition from pauciserial to uniserial.{{Cite web |title=Mammal Species of the World - Browse: Dipodidae |url=https://www.departments.bucknell.edu/biology/resources/msw3/browse.asp?id=12900003 |access-date=2022-04-13 |website=www.departments.bucknell.edu}} Its remains have only been found in the Wind River Basin in Wyoming, and could be found there during the species' existence on Earth.{{Cite journal |last1=Dawson |first1=Mary R. |last2=Krishtalka |first2=Leonard |last3=Stucky |first3=Richard K. |date=1990-06-08 |title=Revision of the Wind River faunas, early Eocene of central Wyoming. IX - The oldest known hystricomorphous rodent (Mammalia: Rodentia) |url=https://ntrs.nasa.gov/citations/19930060906 |journal=Carnegie Museum of Natural History, Annals |language=en |volume=59 |issue=2 |doi=10.5962/p.240768 |issn=0097-4463|doi-access=free }} It was previously assumed that Armintomys belonged to the Dipodoidea family, but has since been understood to have been part of an early radiation of dipodoid rodents, but was not directly ancestral to any later dipodoids, thus it was recategorized into its own family.{{Cite book |last=Korth |first=William W. |url=https://books.google.com/books?id=EBH3BwAAQBAJ&dq=Armintomys+tullbergi&pg=PA253 |title=The Tertiary Record of Rodents in North America |date=2013-11-21 |publisher=Springer Science & Business Media |isbn=978-1-4899-1444-6 |language=en}}