LIZARDS AND TURTLES OF WESTERN CHIHUAHUA Wilmer W. Tanner' Abstract — This second report on the reptiles of Chihuahua deals with the lizards and turtles of western Chihuahua. Field work was done from 1956 to 1972 and was confined to the area west of Highway 45. General information pertaining to the ecology and geolog\' reported in the section on snakes is not repeated. Ecological and life history information is included in the species accounts where data are available. In western Chihuahua 16 genera and 49 species and subspecies of lizards and 3 genera and 5 species of turtles are reported. Onl\ one subspecies is described as new (Sceloponts poinsettii robisoni), and added data strengthen the diagnosis of others. Three genera {Sceloponts, Cnemidophorus, and £i/?nect's) contain 28 of the species and subspecies reported. This is the second article of three on the herpetofauna of the Mexican state of Chi-huahua. Article one presented data on the snakes, as well as general information; these will not be repeated. The present report deals with the lizards, a major segment of the reptil-ian fauna of this state, and briefly with the turtles collected during the various trips. While we at no time concentrated on finding representatives of the order Testudines, we did include them in the collection when found. Therefore, only the scientific name and locality is included in this report. Perhaps the most complete listing of the lizard and turtle species to date is Smith and Taylor (1950). In their report, 14 genera, 32 species, and 5 additional subspecies of lizards are listed, as are 3 genera and 4 species of turtles. As with the serpents, numerous re-ports have included lizards and turtles from Chihuahua, but none have been designed to examine as a unit the species occurring in this Mexican state. Field work was done along Highway 45 from Ciudad Juarez south to the Durango bor-der. No attempt was made to collect east of the highway. Our efforts were, therefore, in areas west of Highway 45, including eight trips into the mountains west of Colonia Juarez and west and southwest of Chihuahua City. We did not enter the Sierra del Nido, an area being investigated by Dr. J. D. Ander-son. Collecting was done from May into Octo-ber 1956-1972. This schedule of trips permit-ted us to be in Chihuahua during the dry season. May and June, the wet season, from July into early September, and after the heavy summer rains in late September and October. It should be noted that Chihuahua does not have a predictable wet season. Some years the summer rains are spotty, the dry season ex-tending well into July. When the rains do come, there is a major transformation of the entire area. What was apparently a dry, bar-ren hillside soon becomes a green, grassy meadow between the desert shrubs. In the fall, fields of grass, knee-to hip-high, soon develop in the open areas (Fig. 1). The altitudinal changes, from about 5,000 feet in the desert valleys east of the mountains to the mountains ranging from 7,500 to 9,000 feet, provide a variety of habitats extending west to the Continental Divide. The more gradual ascent from the east is in great con-trast to the more sudden descent into the deep can) ons and escarpments of the west, particularly in the tributaries of the Rio El Fuerte of the southwest. This altitudinal change influences the flora, ranging from desert shrubs in the valleys to the extensive oak and pine forests in the mountains. For the lizards, as was true for the snakes (Tanner 1986), the western highlands have provided for species whose range is restricted to moun-tains and whose distribution is basically south into Durango rather than north. During the years (1956-1972) spent in Chi-huahua, the habitats (desert valleys, foothills, and western mountains) were being used but not badly abused. Open areas near towns and M L Bean Life Science Museum, Brigham Young University, Provo, Utah rH4602. 383
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