New York, N.Y. : American Museum of Natural History
Abstract
16 p. : ill. ; 26 cm.Includes bibliographical references (p. 15-16)."Derived characters of the incisive foramen, infraorbital canal, sphenopalatine foramen, transvere canal, sphenopterygoid foramen, carotid canal, and temporal foramina are shared by eomyids and geomyoids (Geomyidae and Heteromyidae). Three of these characters are shared with myoxoids, dipodoids, and muroids. These facts support the hypothesis that eomyids and geomyoids had common ancestry in a stem species from which no other rodent groups are descended. The family Eomyidae is raised to equal rank, Eomyoidea. Likewise, the inclusive infraorder Geomorpha and rodents traditionally considered myomorphs shared unique common ancestry and are placed together in the suborder Myomorpha. Yoderimys and Kansasimys are primitive in the infraorbital canal and lack of interorbital foramen, but Kansasimys shares derived tooth crown morphology with other eomyoids. The skull of Kansasimys is distinguished by large size and by peculiarities of the premaxillary-maxillary suture, temporal-supraorbital crests, and occiput; the teeth resemble those of Adjidaumo"--P. [1]
