''Propalaeocastor'' is a poorly known extinct

genus Genus (; : genera ) is a taxonomic rank above species and below family (taxonomy), family as used in the biological classification of extant taxon, living and fossil organisms as well as Virus classification#ICTV classification, viruses. In bino ...

beaver Beavers (genus ''Castor'') are large, semiaquatic rodents of the Northern Hemisphere. There are two existing species: the North American beaver (''Castor canadensis'') and the Eurasian beaver (''C. fiber''). Beavers are the second-large ...

s (family

Castoridae Castoridae is a family of rodents that contains the two living species of beavers and their fossil relatives. A formerly diverse group, only a single genus is extant today, ''beaver, Castor.'' Two other genera of "giant beavers", ''Castoroides'' ...

) from the early

Oligocene The Oligocene ( ) is a geologic epoch (geology), epoch of the Paleogene Geologic time scale, Period that extends from about 33.9 million to 23 million years before the present ( to ). As with other older geologic periods, the rock beds that defin ...

Europe Europe is a continent located entirely in the Northern Hemisphere and mostly in the Eastern Hemisphere. It is bordered by the Arctic Ocean to the north, the Atlantic Ocean to the west, the Mediterranean Sea to the south, and Asia to the east ...

and

Asia Asia ( , ) is the largest continent in the world by both land area and population. It covers an area of more than 44 million square kilometres, about 30% of Earth's total land area and 8% of Earth's total surface area. The continent, which ...

. 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'' and '' Anchitheriomys''.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 a continental area on Earth, comprising all of Europe and Asia. According to some geographers, Physical geography, physiographically, Eurasia is a single supercontinent. The concept of Europe and Asia as distinct continents d ...

n castorine '' Steneofiber''.

References

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