Holotype.—University of Michigan Museum of Zoology No. 119542, from Capirio, Michoacán, México (185 meters), an adult male, one of a series collected on June 13, 1958, by William E. Duellman, Jerome B. Tulecke, and John Wellman. Original number WED 12310.
Paratopotypes.—UMMZ Nos. 119536-119541 and 119543-119550.
Diagnosis.—A race of Cnemidophorus sacki characterized by large size (more than 130 mm. snout-vent length in males), approximately 106 dorsal granules around the midbody, about 41 femoral pores, and a dorsal color-pattern in adult males consisting of lateral and dorsolateral rows of spots, paravertebral rows fused with middorsal light green area at least anteriorly, and pink throat having a median light blue spot or transverse band.
Description of Holotype.—Snout-vent length, 128 mm.; tail length, 252 mm.; tail/body ratio, 1.97; scutellation typical of sacki—four supraoculars, enlarged postantebrachials, and enlarged mesoptychials; 107 granules around midbody (excluding enlarged ventrals); 45 femoral pores; three enlarged preanal scales; supraorbital semicircle-series extending anteriorly to posterior edge of frontal ([Fig. 1]).
Top of head and nape dusty brown; tip of rostral and lateral edges of superciliaries dark cream-color; upper labials and sides of head anterior to eyes cream-color, mottled with blue; lower labials and postocular region pale blue; mental, postmental, and sublabials cream-color. Upper surfaces of forelimbs dull bluish gray, spotted with pale greenish yellow; dorsal surfaces of proximal one-fourth of tail light brownish gray turning to pale orange-brown posteriorly; lateral surfaces of tail bluish gray anteriorly and creamy brown posteriorly. Nuchal region light bluish gray; flanks dark gray; dorsal ground-color dark brown, somewhat paler posteriorly. Body having a row of cream-colored spots in place of a lateral stripe, and another row in place of dorsolateral stripe; dorsally, large diffuse tan or light green spots partially fused and tending to form irregular transverse markings. Chin to posterior end of sublabials pale pink, bordered posteriorly by bluish white area, and then pink. Mesoptychials, under surfaces of hind limbs, and belly cream-colored; anterior edges of belly scales dark blue; lateral two rows of ventrals on posterior two-thirds of body dark blue having light blue or cream-colored spots. Under surfaces of forelimbs bluish cream; ventral surface of tail cream-colored.
Variation in Size and Scutellation.—The largest male has a snout-vent length of 132 mm., the largest female, 114 mm., and the smallest juvenile, 34 mm. The number of dorsal granules at the midbody varies from 91 to 117 (106.2 ± 0.43); the ratio of the number of granules between the paravertebral stripes to the number of granules around the body (PV/GAB) varies from 0.064 to 0.157 (0.097 ±0.007); the number of femoral pores varies from 32 to 49 (41.1 ± 0.20). Usually there are only three enlarged preanals, but 18 specimens have a somewhat enlarged scale anterior to the normal complement of three. In 15 specimens the supraorbital semicircle-series terminate short of the posterior edge of the frontal; in the others the series reach the frontal.