Wahlert, John H.2005-10-062005-10-061985http://hdl.handle.net/2246/522020 p. : ill. ; 26 cm.Includes bibliographical references (p. 18-20)."Analysis of cranial and mandibular morphology, especially the foramina and structures relating to the masticatory musculature, supports monophyly of the living Heteromyidae. The family includes two major divisions, the Heteromyinae on the one hand, and the Perognathinae and Dipodomyinae on the other. Derived features of Schizodontomys suggest that the genus may be an early member of the Dipodomyinae. The Heteromyidae and Geomyidae, containing only the Geomyinae, share common ancestry. The Entoptychidae are tentatively placed as the sister group of these two families; the Florentiamyidae appear to be the earliest known branch of the geomyoid clade. The Geomyoidea, which includes these families, and the extinct Eomyoidea comprise the infraorder Geomorpha. A classification of the Geomorpha that reflects these phylogenetic hypotheses is presented"--P. [1].3113608 bytesapplication/pdfen-USQL1 .A436 no.2812, 1985Geomyoidea.Rodents -- Anatomy.Rodents -- Phylogeny.RodentsSkull -- Anatomy.Rodents, Fossil -- North America.Mammals, Fossil -- North America.Paleontology -- Tertiary -- North America.Paleontology -- North America.text