What is "castoroides"

Castoroides \Castoroides\ n. a genus of extinct beavers of the Pleistocene; of eastern and southern U.S.

Syn: genus Castoroides.

Castoroides, or giant beaver, is an extinct genus of enormous beavers that lived in North America during the Pleistocene. C. leiseyorum and its northern sister species Castoroides ohioensis, were the largest beavers to ever exist.