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Populations of the same species that inhabit contrasting environments may be subject to different selection pressures, promoted by the local environment. Therefore, the individuals of the different populations respond to these pressures with adaptations to local environments; however, not all species or populations respond in the same way. We compared some morphological and ecological traits of the lizard Sceloporus mucronatus that inhabits contrasting environments in central Mexico. The results show male-biased sexual size dimorphism in Tecocomulco, but no differences in size between sexes in Parque Nacional El Chico (PNCH). Significant differences were observed in morphometric traits and in body mass between sexes and populations, but not in the interaction between these two factors. In general, females were heavier than males, while males had larger head structures, jaws, and hind limbs than females. In addition, differences were recorded in the volume of the abdomen, which was female-biased in the PNCH, and male-biased in Tecocomulco. Between populations, it was recorded that the organisms from the PNCH were heavier and had larger heads than those from Tecocomulco. Thermal traits showed differences among populations, but not between sexes nor in the interaction among these factors. Individuals from the locality with lower temperature and higher precipitation (PNCH) reached higher body temperatures and used warmer microhabitats than those individuals from the locality with higher temperature and lower precipitation (Tecocomulco). Females from both populations showed a greater degree of active thermoregulation compared to males. In addition, in both sexes and populations, average values of behavioral thermoregulation were different from zero. Significant differences were recorded in microhabitat use between populations. In agreement with previous studies of morphology and thermal ecology carried out in this species from this and other localities, and in different years, we suggest that its populations present a wide phenotypic plasticity. Highlights: Sceloporus mucronatusis an active thermoregulator. Females from both populations showed higher percentages of negative values of behavioral thermoregulation compared to males. Males have larger head structures, jaws, and hind limbs than females. Between populations, differences were recorded in some morphometric and thermal traits, and use of microhabitat. [ABSTRACT FROM AUTHOR]

Plethodontids are organisms highly linked to variations in temperature and moisture in the environment. The major determinant of their body temperature is the interaction between microhabitat preferences and time of day. However, there are proposed differences in moisture and temperature preferences among age classes. This study examines how microhabitat exposure and time of day on the abundance, environmental and microenvironmental moisture and temperature, body temperature, and age demographics of Pseudoeurycea leprosa interact. Hatchlings appeared to be more abundant during the day, and their body temperature varied by microhabitat and time of day, the microenvironmental moisture of the sites that individual used were affected by the interaction between these variables. These results suggest segregation between age classes. Juveniles and adults may benefit by exploiting exposed microhabitats because their body temperature remains stable. These findings highlight the importance of understanding the responses of plethodontids to changes in their environment. [ABSTRACT FROM AUTHOR]

Caudal autotomy is a behaviour in lizards that favours survival but brings with it some associated costs, mainly loss of energy, which is related to the position of the breaking point. Moreover, the frequency of tail loss can vary at different levels, between sexes, populations, seasons and at an intra-and inter-population level. In this study, we analysed the breaking position of the tails in individuals and frequencies of tail loss between years, sexes, seasons and populations of the lizard Sceloporus variabilis that inhabit contrasting environments. The results showed a low frequency of tail loss at the ends (distal and proximal) of this organ (except for individuals from the xeric scrubland population) and there was a higher proportion of complete than incomplete tails in lizards for all analysed populations. Also, there was no variation in the frequency of tail loss among populations, sexes (except in one population), years or seasons. A higher proportion of organisms with complete tails suggests that this organ is an important element for these lizards. In addition, the lack of variation in the frequency of tail loss may indicate a similar behaviour such as escape from predators among the groups analysed. [ABSTRACT FROM AUTHOR]