A New Species of Heteromyid Rodent from the Middle Oligocene of Northeast Colorado with Remarks on the Skull

BY

EDWIN C. GALBREATH

University of Kansas Publications
Museum of Natural History

Volume 1, No. 18, pp. 285-300, 2 plates
August 16, 1948

University of Kansas
LAWRENCE
1948


University of Kansas Publications, Museum of Natural History

Editors: E. Raymond Hall, Chairman; H. H. Lane, Edward H. Taylor

Volume 1, No. 18, pp. 285-300, 2 plates
August 16, 1948

University of Kansas
Lawrence, Kansas

PRINTED BY
FERD VOILAND, JR., STATE PRINTER
TOPEKA, KANSAS
1948


22-3342

Plate 2. Heliscomys tenuiceps. Univ. Kans. Mus. Nat. Hist., Vert. Paleo. Coll. No. 7702. A, dorsal view; B, lateral view; C, ventral view. All views approximately × 5.

Plate 3. Heliscomys tenuiceps. Univ. Kans. Mus. Nat. Hist., Vert. Paleo. Coll. No. 7702. A, lateral view of right side of skull showing structures in orbital area. ALS, alisphenoid. FR, frontal. MAX, maxillary. OS, orbitosphenoid. PAL, palatine. PC, presphenoid canal. SF, sphenoidal fissure. SFr, sphenofrontal foramen. SPal, sphenopalatine foramen. Approximately × 9.3; B, occlusal view of P4-M3. Approximately × 23.4.

New Species of Heteromyid Rodent from the Middle Oligocene of Northeast Colorado with Remarks on the Skull

By

EDWIN C. GALBREATH

Heretofore our knowledge of the osteology of Heliscomys Cope has been extremely limited; this genus previously was known by its teeth, fragmental maxillaries, incomplete palatine bone and mandible, and part of one forelimb. In the summer of 1946 the writer, as a member of the University of Kansas Museum of Natural History field party, discovered the anterior part of a skull of Heliscomys in the middle Oligocene deposits of Logan County, Colorado. This specimen, representing a new species, yields a welcome, and greatly desired addition to our fund of information about the genus.

The writer is indebted to Dr. Robert W. Wilson for advice and helpful criticism in the course of this study, and to Mr. Bryan Patterson of the Chicago Natural History Museum for the loan of comparative material. Mrs. Bernita Mansfield of the Geology Department, University of Kansas, prepared the plates.

Family HETEROMYIDAE

Heliscomys tenuiceps, new species

Holotype.—Anterior part of a skull with left P4-M3, No. 7702, Vertebrate Paleontological Collection, Museum of Natural History, University of Kansas.

Geological Age and locality.—Silts of Orellan age in the Cedar Creek facies of