Ischyromys

Taxobox
name = "Ischyromys"
status = fossil
fossil_range = Early Eocene - Early Oligocene
regnum = Animalia

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image_width = 250px
image_caption = "Ischyromys" skeleton, Smithsonian National Museum of Natural History
phylum = Chordata
classis = Mammalia
ordo = Rodentia
subordo = Sciurognathi
familia = Ischyromyidae
genus = "Ischyromys"
genus_authority = Leidy, 1856
subdivision_ranks = Species
subdivision =
* "I. typus" (type)
* "I. blacki"
* "I. douglassi"
* "I. junctus"
* "I. veterior"

"Ischyromys" is an extinct genus of rodent from North America.

The 60 cm (2 ft) long creature is one of the oldest rodents known. It resembled a mouse and already had characteristic rodent incisors. "Ischyromys"'s hind legs were longer than the forelegs, which could be used for other means than walking. Unlike most other mammals of its time, "Ischyromys" was arboreal (along with its relative "Paramys"). It was a well-adapted climber that gradually beat out competition from rodent-like arboreal plesiadapiform primates.