''Propalaeocastor'' is a poorly known extinct genus of

beaver Beavers are large, semiaquatic rodents in the genus ''Castor'' native to the temperate Northern Hemisphere. There are two extant species: the North American beaver (''Castor canadensis'') and the Eurasian beaver (''C. fiber''). Beavers ar ...

s (family Castoridae) from the early

Oligocene The Oligocene ( ) is a geologic epoch of the Paleogene Period and extends from about 33.9 million to 23 million years before the present ( to ). As with other older geologic periods, the rock beds that define the epoch are well identified but the ...

of Europe and Asia. Recently described material of a new species of ''Propalaeocastor'', ''P. irtyshensis'', indicates the genus is probably the earliest known member of the subfamily Castorinae, which includes all castorids more closely related to living

s (genus ''Castor'') than to the extinct giant beaver (genus ''Castoroides''). Previously, ''Propalaeocastor'' had been allied with more basal beavers such as ''

Agnotocastor ''Agnotocastor'' is an extinct member of the beaver family Castoridae. Unlike its modern relative, this species took the place of muskrats in the rivers of North America during the Oligocene The Oligocene ( ) is a geologic epoch of the Paleo ...

'' and ''

Anchitheriomys ''Anchitheriomys'' is an extinct member of the beaver family, Castoridae. It inhabited North America and Eurasia during the middle Miocene. The name of the genus comes from ''Anchitherium'', an extinct genus of Equidae, horses, and the Greek lang ...

''.Korth W.W., 2002. Comments on the systematics and classification of the beavers (Rodentia, Castoridae). ''Journal of Mammalian Evolution'' 8(4):279-296. According to Wu and coauthors, ''Propalaeocastor'', specifically ''P. butselensis'', is the likely ancestor of the better-known Eurasian castorine ''

Steneofiber ''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 ...

''.

References

Prehistoric beavers Oligocene rodents Oligocene mammals of Asia Oligocene mammals of Europe Prehistoric rodent genera Fossil taxa described in 1967 {{paleo-rodent-stub