''Steneofiber'' is an 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 from the

Miocene The Miocene ( ) is the first epoch (geology), geological epoch of the Neogene Period and extends from about (Ma). The Miocene was named by Scottish geologist Charles Lyell; the name comes from the Greek words (', "less") and (', "new") and mea ...

. 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. Steneofiber esseri

These small, 30-cm-long (1-ft-long) creatures probably lived in large

freshwater Fresh water or freshwater is any naturally occurring liquid or frozen water containing low concentrations of dissolved salts and other total dissolved solids. The term excludes seawater and brackish water, but it does include non-salty mi ...

lake A lake is often a naturally occurring, relatively large and fixed body of water on or near the Earth's surface. It is localized in a basin or interconnected basins surrounded by dry land. Lakes lie completely on land and are separate from ...

s, like present day beavers. A

semiaquatic In biology, being semi-aquatic refers to various macroorganisms that live regularly in both aquatic and terrestrial environments. When referring to animals, the term describes those that actively spend part of their daily time in water (in ...

lifestyle is indicated by the presence of combing-claws, which living beavers use to waterproof their fur. Most likely, it was incapable of bringing down trees like its modern relatives. ''Steneofibers'' were more terrestrial than modern beavers, living in

burrow file:Chipmunk-burrow (exits).jpg, An eastern chipmunk at the entrance of its burrow A burrow is a hole or tunnel excavated into the ground by an animal to construct a space suitable for habitation or temporary refuge, or as a byproduct of Animal lo ...

s, but fossils are still found near ancient water sources. The finding of a possible family group of ''Steneofiber'' skeletons in

France France, officially the French Republic, is a country located primarily in Western Europe. Overseas France, Its overseas regions and territories include French Guiana in South America, Saint Pierre and Miquelon in the Atlantic Ocean#North Atlan ...

has been used to infer that the genus employed a

K-selected In ecology, selection theory relates to the natural selection, selection of combinations of Trait (biological), traits in an organism that trade off between quantity and quality of offspring. The focus on either an increased quantity of offsprin ...

reproductive strategy like modern beavers, in which extensive parental care is given to a small number of offspring. ''Steneofibers'' are among the earliest known members of the

subfamily In biological classification, a subfamily (Latin: ', plural ') is an auxiliary (intermediate) taxonomic rank, next below family but more inclusive than genus. Standard nomenclature rules end botanical subfamily names with "-oideae", and zo ...

Castorinae, which includes beavers more closely related to the two living species than to the recently

extinct Extinction is the termination of an organism by the death of its Endling, last member. A taxon may become Functional extinction, functionally extinct before the death of its last member if it loses the capacity to Reproduction, reproduce and ...

giant beaver. It is probably directly descended from the earliest known castorine, '' Propalaeocastor''.

References

Prehistoric beavers Prehistoric rodent genera Miocene mammals of Europe Oligocene mammals of Europe Miocene rodents Oligocene rodents Taxa named by Étienne Geoffroy Saint-Hilaire Fossil taxa described in 1833 {{paleo-rodent-stub