Spatio-Temporal Evaluation of Some Morphological Traits of the Viviparous Lizard Sceloporus mucronatus (Squamata: Phrynosomatidae), a Species with a High Risk of Extinction

Morphological adaptations of individuals are determined by different environmental and/or genetic factors. Depending on locality and sex, these adaptations may vary in different ways. Therefore, the objective of this study is to evaluate some morphological (morphometric) traits over time in different populations of Sceloporus mucronatus , a species endemic to Mexico with a high risk of extinction. The results showed significant differences at the intrapopulation level, male-biased in size, head, jaw structures, and limbs; however, females showed a greater interaxillary distance, although the difference was not significant in all populations and years. Among populations and years, significant differences were recorded in the size of the males. In females, the differences were in the size and the interaxillary distance. A significant and positive relationship was found between snout–vent length and temperature, precipitation, and elevation in females, and between snout–vent length and elevation in males; however, the association was very low. The morphological variation observed among populations of S. mucronatus suggests that this species has a wide degree of phenotypic plasticity, and therefore could adapt to different environmental conditions. However, the morphological variation recorded in this study is not strongly associated with some of the environmental variables analyzed; therefore, it is necessary to carry out further studies (behavior, thermal ecology, and diet, among others) to understand how this species is responding to environmental changes, mainly those generated by humans.