Energetics in Liolaemini lizards: implications of a small body size and ecological conservatism.

Liolaemini lizards occur in southern South America in a variety of dietary habits across a broad latitudinal and altitudinal distribution. We studied standard metabolic rates of 19 Liolaemini species and analyzed these data using both conventional and phylogenetically informed statistics. Oxygen consumption showed a significant and positive relationship with body mass (SMR = 0.109 × body mass(0.876±0.023)), with a higher slope than that expected on the basis of the three-quarter power law model. After phylogenetically informed and conventional analyses, no significant differences in metabolic rates were found to be related to diet or elevation. We hypothesize that small body size, ecological conservatism and physiological compensation may explain the lack of differences in metabolic rates observed among these lizards.