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Fig. 2. Diagrammatic representation of ontogenetic change in color pattern in Cnemidophorus sacki zweifeli: A—hatchling, 34 mm. snout-vent length; B—juvenile, 55 mm. snout-vent length; C—subadult male, 80 mm. snout-vent length; D—small adult male, 100 mm. snout-vent length; E—large adult male, 120 mm. snout-vent length.
Geographic variation.—No noticeable geographic variation in this subspecies is evident in the series from the Tepalcatepec Valley. However, lizards from eastern Michoacán (Chinapa, 6 km. N of Tafetan, 6 km. S of Tzitzio, and 19 km. S of Tzitzio) differ slightly from those from the Tepalcatepec Valley; the eastern specimens have fewer dorsal granules and femoral pores, and a higher ratio of dorsal granules between the paravertebral stripes to the number of granules around the body (see Tables 1-3). No large adult males are present in the eastern series; the subadults and small adult males have color patterns like lizards of similar size from the Tepalcatepec Valley. The largest male from the east has a snout-vent length of 110 mm., rows of pale spots, and no trace of brown and tan cross-bars. Specimens of Cnemidophorus sacki sacki of equal size from Guerrero, Morelos, and Puebla in the upper Balsas Basin have a tan dorsum with dark brown cross-bars. The localities in eastern Michoacán are intermediate geographically between the Tepalcatepec Valley and the known range of the nominal subspecies in the upper Balsas Basin. In characters of scutellation specimens from the east are intermediate between C. sacki sacki and C. sacki zweifeli in the Tepalcatepec Valley. However, in coloration the lizards from the east are like those from the Tepalcatepec Valley, but differ distinctly from the nominal subspecies. Therefore, the eastern series is referred to the subspecies C. sacki zweifeli.
Comparisons.—Four other species of Cnemidophorus occur in the Tepalcatepec Valley with Cnemidophorus sacki zweifeli. Of these, C. calidipes has a maximum snout-vent length of 79 mm., 66 to 86 dorsal granules, and a light brown dorsum with pale blue spots and vertical bars; C. communis communis has a maximum snout-vent length of 135 mm., 105 to 144 dorsal granules, and a greenish tan dorsum with yellow spots; C. deppei infernalis has a maximum snout-vent length of 84 mm., 91 to 120 dorsal granules, and a striped pattern throughout life; and C. lineatissimus exoristus has a maximum snout-vent length of 98 mm., 108 to 135 dorsal granules, and a middorsal yellow stripe and vertical bars on the flanks. Both calidipes and communis are like sacki in possessing four enlarged supraoculars and enlarged postantebrachials, whereas deppei and lineatissimus have three enlarged supraoculars and granular postantebrachials. Juveniles of calidipes and sacki are alike in coloration but different in the extent of the supraorbital semicircle-series. In calidipes the supraorbital semicircle-series usually are complete, whereas in sacki the series never extended anterior to the posterior edge of the frontal.
Table 1.—Variation in the Number of Dorsal Granules
in Three Subspecies of Cnemidophorus sacki
| Key for Table: | |
| No. = Number of Specimens | SD = Standard Deviation |
| SE = Standard Error | C/V = Coefficient of Variation |
| Population | No. | Range | Mean | SD | SE | C/V | |
sacki sacki | |||||||
| Entire Sample | 106 | 88-105 | 96.3 | 4.16 | 0.40 | 3.92 | |
| Puebla: Tehuitzingo | 22 | 88-103 | 95.1 | 4.18 | 0.89 | 4.39 | |
| Guerrero: Chilpancingo | 23 | 90-105 | 95.8 | 3.86 | 0.80 | 4.02 | |
| Guerrero: Mexcala | 22 | 90-102 | 96.5 | 3.56 | 0.76 | 3.69 | |
| Morelos | 39 | 89-105 | 97.2 | 4.56 | 0.73 | 4.69 | |
| sacki zweifeli | |||||||
| Entire Sample | 191 | 91-117 | 106.2 | 5.98 | 0.43 | 3.13 | |
| Michoacán: Tafetan | 21 | 91-116 | 101.4 | 8.04 | 1.75 | 7.92 | |
| Michoacán: Apatzingán | 170 | 95-117 | 106.8 | 5.42 | 1.32 | 3.19 | |
| sacki occidentalis[A] | 62 | 97-118 | 106.3 | 4.72 | 0.60 | 7.61 |