''Propalaeocastor'' is a poorly known extinct

genus Genus ( plural genera ) is a taxonomic rank used in the biological classification of extant taxon, living and fossil organisms as well as Virus classification#ICTV classification, viruses. In the hierarchy of biological classification, genus com ...

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 The family Castoridae contains the two living species of beavers and their fossil relatives. A highly diverse group of rodents within this family once roamed the earth, but only a single genus is extant today, '' Castor''. Characteristics C ...

) 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 ...

Europe Europe is a large peninsula conventionally considered a continent in its own right because of its great physical size and the weight of its history and traditions. Europe is also considered a Continent#Subcontinents, subcontinent of Eurasia ...

and

Asia Asia (, ) is one of the world's most notable geographical regions, which is either considered a continent in its own right or a subcontinent of Eurasia, which shares the continental landmass of Afro-Eurasia with Africa. Asia covers an area ...

. 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 The muskrat (''Ondatra zibethicus'') is a medium-sized semiaquatic rodent native to North America ...

'' 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

Eurasia Eurasia (, ) is the largest continental area on Earth, comprising all of Europe and Asia. Primarily in the Northern and Eastern Hemispheres, it spans from the British Isles and the Iberian Peninsula in the west to the Japanese archipelago a ...

n 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