Agnotocastor

{{Short description|Extinct genus of rodents}}

{{Automatic taxobox

| fossil_range = Late Eocene–Early Oligocene, {{Fossil range|37.2|26.3|ref=}}

|taxon = Agnotocastor

|authority = Stirton, 1935

|type_species = †Agnotocastor praetereadens

|subdivision_ranks = Species

|subdivision =

• †A. coloradensis
• †A. galushai
• †A. montanus
• †A. praetereadens
• †A. readingi

}}

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 epoch. The earliest species is A. galushai, which is also the first reliable member of the Castoridae.{{cite journal |last1=Emry |first1=Robert J. |title=A new species of Agnotocastor (Rodentia, Castoridae) from the early Oligocene of Wyoming |journal=American Museum Novitates |date=1972 |issue=2485 |pages=1–7 |url=https://www.biodiversitylibrary.org/bibliography/204990 }} It is known chiefly from North America, with a single record from Central Asia.