Oligocene rodents

Palaeocastor ('ancient beaver') is an extinct genus of beavers that lived in the North American Badlands during the late Oligocene period to early Miocene, 29.5~18.5 million years ago. Palaeocastor was much smaller than modern beavers. There are several species including Palaeocastor fossor, Palaeocastor magnus, Palaeocastor wahlerti, and Palaeocastor peninsulatus. The animals first became known on grounds of their fossilized burrows, the "Devil's corkscrews." ==Biology== thumb|left|P. peninsulates|205x205px Some members of this genus made corkscrew-shaped burrows and tunnels. Like many early

Steneofiber is an extinct genus of beavers from the Miocene. They contain several species of beavers. Amongst them are S.barbouri, S.complexus, S.depereti, S.fossor, S.gradatus, and S.hesperus. Their various species are found all the way from the eastern end of the Iberian peninsula to southern Japan. S.depereti has been found in northwest Germany. thumb|left|Steneofiber esseri at the Gallery of Paleontology and Comparative Anatomy, Paris. These small, 30-cm-long (1-ft-long) creatures probably lived in large freshwater lakes, like present day beavers. A semiaquatic lifestyle is indicated by t

Eomys is an extinct genus of eomyid rodent from the late Oligocene of France, Germany, Spain, and possibly Turkey. The species Eomys quercyi is the earliest known gliding rodent.

Ischyromys is an extinct genus of rodent from North America. thumb|left|Skull

Migmacastor is an extinct member of the beaver family, Castoridae, known from a single species, Migmacastor procumbodens. Only a single specimen has been reported, a skull from the late Oligocene or early Miocene of Nebraska. Features of the incisor teeth of Migmacastor indicate they were used to dig. Other extinct beavers, including the better-known Palaeocastor, were also fossorial (digging), but Migmacastor may have become a burrower independently.

Rhizospalax is a genus of extinct rodent from Europe thought to be distantly related to modern beavers. It is the only member of the family Rhizospalacidae.