HERPETOLOGY OF ZUNI MOUNTAINS — GEHLBACH 281 



in most respects. This northwest-southeast cline may be extended 

 west through the Defiance Plateau, Apache County, Arizona, where 

 I also have taken S. u. tristichus x S. u. elongatus (UMMZ 120280), 

 to Grand Canyon National Park, Coconino County, Arizona (Williams, 

 1960, p. 26). 



In view of this cline, one might question the retention of S. u. 

 tristichus and S. u. elongatus as distinct subspecies. Other salient 

 ecological-morphological differences in New Mexico populations, 

 however, prevent me from lumping these races. With the exception 

 of a few nearl}'' unicolor specimens,* most S. u. elongatus from San 

 Juan County, New Mexico, lack distinct dorsolateral and lateral 

 fight stripes and the spotted lateral pattern figured by Smith (1946, 

 pi. 53 E, G) for S. u. tristichus; furthermore, adults are larger 

 (45-83, X 64 mm. snout-vent, 25 San Juan County specimens) and 

 possesses more fourth-toe lamellae (22-25, x 23.3 ±0.29) than S. u. 

 tristichus x S. u. elongatus (cf. table 5). They are decidedly more 

 scansorial, frequenting large boulders and cliff situations in contrast 

 to marked terrestrial propensities in typical individuals of S. u. 

 tristichus and the Zuni population. 



Although Sceloporus undulatus was the most ubiquitous reptile 

 studied, it did not enjoy the wide elevational range of Phrynosoma 

 douglassi or Thamnophis elegans (fig. 3). The species was most 

 abundant in Roughlands associations, especially the pinyon-juniper. 

 While found to a limited extent at the upper edge of the Plains- 

 Roughlands continuum, S. undulatus usually was outnumbered by 

 S. graciosus, Crotaphytus coUaris, and Cnemidophorus velox in this 

 habitat. Specimens were conspicuously absent from cliffs inhabited 

 by Urosaurus ornatus. They were uncommon on large boulders and 

 the lower trunks of trees. Most individuals utilized elevated sites 

 such as fallen tree trunks for sunning purposes and as apparent vantage 

 points but were distinctly terrestrial in foraging habits. Body 

 temperatures of 10 individuals foraging at 7400 feet were 29-37, 

 (x33.1±0.98)°C. 



Evidence presented by Anderson (1960, p. 66), Martin (1958, p. 57), 

 and others indicates that reproductive activity in certain reptiles is 

 correlated with the beginning of summer rains. Similar observations 

 on S. undulatus have prompted the following remarks. Plateau 

 lizards carrying well-developed eggs have been found as early as 

 June 13, 1957. Most females over 40 mm. snout-vent held eggs when 

 collected before mid-July, but none taken in August contained eggs. 



* A polychromatic variant occurs, usually uniform dark brown or gray but 

 occasionally with slightly darker or lighter lateral stripes (e.g., see I.egler, 1960, 

 p. 181; Smith, 1946, p. 217). It has been found in the Guadalupe Mounlaiiis, 

 New Mexico (UMMZ 121745), but not in the Zuni region. 



