Field thermal biology in an altitudinal and latitudinal gradient in Phymaturus punae, P. zapalensis and P. tenebrosus (Iguania, Liolaemidae)

NORA R. IBARGUENGOYTIA, JUAN CARLOS ACOSTA, JORGELINA M. BORETTO, HÉCTOR J. VILLAVICENCIO,JOSÉ A. MARINERO AND J. D. KRENZ

JOURNAL OF ARID ENVIRONMENTS

ACADEMIC PRESS LTD-ELSEVIER SCIENCE LTD

Año: 2008 vol. 72 p. 1620 - 1630

0140-1963

The genus Phymaturus (Liolaemidae) is a group of rock-dwelling and viviparous lizards distributed in the highlands of the Andes and on the volcanic plateaus of Patagonia, Argentina. They are restricted to harsh environments characterized by cold-temperate summers and snowy winters that constrain growth, age at sexual maturity, fecundity and length of reproductive cycles.  In the present study the field body temperatures of Phymaturus punae, Phymaturus zapalensis and Phymaturus tenebrosus distributed along a latitudinal and altitudinal gradient are analysed in relation to differences in their life histories. Each of the three species show differences in their body temperatures depending if they are inside or outside the rock crevices. As was expected, body temperatures of lizards inside the rock crevices follow the air and substrate temperatures, but outside the crevices, a paradox was observed. P. zapalensis, living in the most-temperate climate and with body temperatures no different than P. tenebrosus, unexpectedly had lower body temperatures than P. punae, living at 4000 m elevation. Our results suggest that diet, the ability to be active over a broad thermal range, and a longer activity season can counteract the effect of body temperature on the timing and allocation of energy to growth, maturation and reproduction.