to differences in desert vegetation structure; relatively larger lizards 

 being more successful in relatively shaded habitats. Small body size 

 may be of selective advantage during decreases in vegetation density or 

 during increases in the extremes or instabilities of climate. 



5. Axtell, R. W. 1959. Amphibians and reptiles of the Black Gap 

 Wildlife Management Area, Brewster County, Texas. SOUTHWESTERN 

 NATURALIST H2): 88-109. 



The area is described and ecological differences between Cnemi- 

 dophorus inornatus heptagrammus and^. tigris marmoratus are discussed. 



6. — . 1961. Cnemidophorus inornatus , the valid name for the Little 

 Striped Whiptail, with the description of an annectant subspecies. 

 COPEIA 1961(2): U8-158. 



The nomenclatural confusion surrounding the lizard now known as 

 Cnemidophorus inornatus is reviewed. The subspecies _C_. i. inornatus and 

 _C. _i_. heptagrammus (occurs in our area) are formally named, diagnosed, 

 and described. Their respective habitats and distributions are discuss- 

 ed, and range maps are provided. 



7. — . 1966. Geographic distribution of the unisexual whiptail 



Cnemidophorus neomexicanus (Sauria: Teiidae)~Present and past. 

 HERPETOLOGICA 22('^): 2^1-253. 



The taxonomic history of the species is briefly reviewed, and a 

 detailed range map is provided. Ecological attributes and interactions 

 of this species with others in the genus are discussed in detail. Two 

 presumed hybrids between^, neomexicanus and C. inornatus are described. 

 The geographic fragmentation of southern populations of _C. neomexicanus 

 is explained in light of the geologic history of the area and a Wiscon- 

 sin or pre-Wisconsin time of origin is suggested for the species. 



8. — . 1977. Ancient playas and their influence on the recent her- 

 petofauna of the northern Chihuahuan Desert, jn TRANSACTIONS OF THE 

 SYMPOSIUM ON BIOLOGICAL RESOURCES OF THE CHIHUAHUAN 

 DESERT REGION, UNITED STATES AND MEXICO. Wauer, R. H. and D. H. 

 Riskind, editors. National Park Service Trans, and Proc. Series, 

 No. 3: 1*93-512. 



The geomorphic history of the region in Chihuahua and New Mexico 

 is considered in detail. Western range margins of Cnemidophorus tessel- 

 atus and _C. tigris marmoratus, southern range margins of _C. inornatus 



