''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 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 ...

or early

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 ...

Nebraska Nebraska ( ) is a landlocked U.S. state, state in the Midwestern United States, Midwestern region of the United States. It borders South Dakota to the north; Iowa to the east and Missouri to the southeast, both across the Missouri River; Ka ...

. Features of the incisor teeth of ''Migmacastor'' indicate they were used to dig. Other

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 ...

beavers, including the better-known '' Palaeocastor'', were also fossorial (digging), but ''Migmacastor'' may have become a burrower independently.Korth, William W.; Rybczynski, Natalia (2003), "A new, unusual castorid (Rodentia) from the earliest Miocene of Nebraska", Journal of Vertebrate Paleontology 23 (3): 667–675, doi:10.1671/2371

References

Prehistoric beavers Oligocene rodents Miocene rodents Cenozoic mammals of North America Monotypic prehistoric rodent genera {{paleo-rodent-stub