High mountains are more than cold peaks: Diverse thermal availability for an endemic lizard

Abstract

High-altitude mountain ecosystems pose extreme thermal challenges for ectotherms, where steep environmental gradients and dynamic climates demand precise thermoregulatory strategies. The Achala Copper Lizard (Pristidactylus achalensis), an endemic species restricted to the Pampa de Achala in central Argentina, offers a unique model to explore these dynamics. This study investigates how environmental heterogeneity, microhabitat diversity, and intrinsic factors such as sex and reproductive condition shape the thermal biology of this highland specialist. By integrating field measurements of body and environmental temperatures with laboratory assessments of thermal preferences and bite force performance, we reveal how fine-scale thermal landscapes and sex-specific strategies drive thermoregulation and ecological performance. Our findings highlight the critical role of basking microhabitats in optimizing body temperatures and the surprising thermal insensitivity of bite force, which supports reproductive and competitive behaviours under variable conditions. As climate change threatens high-altitude ectotherms, understanding these interactions provides essential insights for predicting species’ responses and informing conservation strategies for thermally specialized reptiles like P. achalensis.