. Distribution of mammals in Colorado. Mammals. 1972 ARMSTRONG: COLORADAN MAMMALS 169 Auditory bullae not meeting anteromedi- ally; dorsal color olivaceous or brown- ish buff (except in Perognathus fas- ciatus callistus) 6 6. Tail usually less than 60; angular proc- ess of mandible as long as condyloid process Perognathus fasciatus Tail usually greater than 60; angular process of mandible shorter than con- dyloid process Perognathus apache 7. Five toes on hind foot; total length 280 or less; proximal part of tail bicolor — Dipodomys ordii Four toes on hind foot; total length 300 or more; proxi
. Distribution of mammals in Colorado. Mammals. 1972 ARMSTRONG: COLORADAN MAMMALS 169 Auditory bullae not meeting anteromedi- ally; dorsal color olivaceous or brown- ish buff (except in Perognathus fas- ciatus callistus) 6 6. Tail usually less than 60; angular proc- ess of mandible as long as condyloid process Perognathus fasciatus Tail usually greater than 60; angular process of mandible shorter than con- dyloid process Perognathus apache 7. Five toes on hind foot; total length 280 or less; proximal part of tail bicolor — Dipodomys ordii Four toes on hind foot; total length 300 or more; proximal part of tail black — "Dipodomys spectabilis Perognathus fasciatus Olive-backed Pocket Mouse The olive-backed pocket mouse occurs generally over the northern Great Plains, from southern parts of the Prairie Provinces, south- ward to south-central Colorado. The natural history of the species never has been thor- oughly investigated, and its status in Colorado is poorly understood. The altitudinal range of specimens examined is about 5000 to 7000 feet. Jones (1953) reviewed the geographic dis- tribution and subspecies of Perognathus fas- ciatus. Hayward and Killpack (1956) noted that P. fasciatus and P. apache are allopatric in northeastern Utah. A similar relationship between those two species is indicated in south-central Colorado, where they are sepa- rated by the Sangre de Cristo Range. Perog- nathus fasciatus is sympatric over a broad area in Colorado with P. favescens, P. flavus, and P. hispidus. Relationships of the nominal spe- cies P. fasciatus and P. apache are under study by Mr. D. F. Williams of the Museum of Southwestern Biology, University of New Mexico. Maxell and Brown (1968) discussed the ecological distribution of P. fasciatus in east- ern Wyoming. The few individuals captured all were taken in a Bouteloua-Stipa commu- nity, indicating a predilection for sites with low, closely-spaced vegetation, and a sub- strate of loamy sand. The pattern of occur-
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Keywords: ., bookcentury1900, bookcollectionbiodiversity, booksubjectmammals
