Thermal biology of the southernmost lizards in the world: Liolaemus sarmientoi and Liolaemus magellanicus from Patagonia, Argentina

IBARGUENGOYTIA, N. R., MEDINA, S.M., FERNÁNDEZ, J. B., GUTIÉRREZ, J. A., TAPPARI, F., SCOLARO, A.

JOURNAL OF THERMAL BIOLOGY

PERGAMON-ELSEVIER SCIENCE LTD

Año: 2010 vol. 35 p. 21 - 27

0306-4565

We determined the efficiency of thermoregulation by the southernmost liolaemids Liolaemus sarmientoi and L. magellanicus from Patagonia, Argentina (511S), by measuring body (T b ), microenvironmental, and operative  temperatures  in  the  field,  and  preferred  body  temperatures  in  the  laboratory  (T pref ). L. sarmientoi was found to be a poor thermoregulator, whereas L. magellanicus was deemed to be a constrained thermoconformer. Among all known species of Liolaemus, L. sarmientoi and L. magellanicus had the lowest T b’ s when tested in the field; however, their T pref’ s were similar to other liolaemids. These  data  suggest  that  these  southernmost  liolaemid  species  have  not  evolved  appropriate thermoregulatory behaviors or made adequate physiological adaptations to face the extreme thermalchallenges of their environment.