Variation of meristic characteristics among populations of the lizard Sceloporus variabilis (Squamata: Phrynosomatidae) from central Mexico

Lizard species of wide distribution can show differences in morphology and many other characteristics, in particular in the scutelation. In this study, we analyzed the variation of 22 meristic characters between sexes and among populations of Sceloporus variabilis from the state of Hidalgo in central Mexico. The variables such as dorsal scales, scales around the body, ventral scales, femoral pores, interfemoral scales, and lamellae of the fourth digit of the hindlimbs were different among populations; the population of San Pablo Tetlapayac presented the highest average values in these variables. A positive and significant relationship between snout-vent length and the number of ventral scales was found only in the females of San Pablo Tetlapayac and Santa Catarina. The variations recorded in the present study indicate an effect of environmental variation in the pattern of the number of scales, and suggest that both environmental conditions, such as precipitation and temperature, and ecological conditions, such as substrate or microhabitats, may be influencing differences in the number and size of scales among populations. Further studies on physiology and ecomorphology are necessary to determine the direction of variations in scutelation between sexes and populations.