Comparative thermal ecophysiology in Pristidactylus scapulatus populations from the Puna region of Argentina

GÓMEZ ALÉS RODRIGO; ACOSTA JUAN CARLOS; VALDEZ FRANCO; MARTINEZ TOMÁS AGUSTÍN; ACOSTA RODRIGO; RODRIGUEZ MUÑOZ MELINA JESÚS; FERNANDEZ RUBEN; CORRALES LUCAS

ZOOLOGY

ELSEVIER GMBH

Año: 2021 vol. 145

0944-2006

Reptiles are important models for understanding fundamental aspects of physiological ecology and for assessinghow environmental change can impact biodiversity. Abiotic factors (micro-environmental temperatures, operative temperatures, thermal quality) may vary geographically along an altitudinal and latitudinal gradient, andtherefore the different thermal resources available for thermoregulation also vary. Comparative analyses amongpopulations provide an opportunity to understand how variation in abiotic factors can affect differentecophysiological traits of a species at different geographical points. Our objective was to carry out a comparativestudy between two populations of Pristidactylus scapulatus in the Puna region of Argentina, providing the frstdata available on thermal ecophysiology, thermoregulatory effciency and locomotor performance of the species.We determined feld body temperature, micro-environmental temperatures and operative temperatures. In thelaboratory, we measured preferred temperatures and calculated the index of thermoregulatory effciency. Inaddition, we recorded critical temperature (minimum and maximum) and we estimated the thermal sensitivity oflocomotion by measuring sprint speed at different body temperatures; based on these data we calculated theoptimal temperature for performance, the optimal performance breadth and thermal safety margin. Air temperatures and operative temperatures were different between sites. However, we only found differences betweenpopulations in the minimum critical temperatures, with these being lower at higher latitude. We note thatP. scapulatus populations adjust optimal temperatures of performance to feld body temperatures and preferredtemperatures, which could reduce the costs of thermoregulation in lizards with limited daily activity and whoinhabit sites with variable and unpredictable environment temperatures. We conclude that Pristidactylus scapulatus has thermal sensitivity in locomotor performance, is a moderate thermoregulator with respect to theenvironment and is a eurithermic lizard, which has thermal flexibility in the cold.