Wahlert, John H.2005-10-062005-10-061977http://hdl.handle.net/2246/20248 p. : ill. ; 26 cm.Includes bibliographical references (p. 7-8)."Derived characters of the sphenopalatine, interorbital, and dorsal palatine foramina are shared by the Eutypomyidae and Castoridae. These support the hypothesis that the two families had common ancestry in a stem species from which no other rodent groups are descended. The two families may be included in a monophyletic superfamily, Catoroidea"--P. [1].4692598 bytesapplication/pdfen-USEutypomys thomsoni.Skull.Rodents, Fossil -- West (U.S.)Mammals, Fossil -- West (U.S.)Paleontology -- Oligocene -- West (U.S.)Paleontology -- West (U.S.)text