Thermal biology of Liolaemus occipitalis (Squamata, Tropiduridae) in the coastal sand dunes of Rio Grande do Sul, Brazil.

The thermal biology of the small sand lizard, Liolaemus occipitalis, was studied in the coastal sand dunes at Quint?o Beach (Palmares do Sul, Rio Grande do Sul, Brazil; 30 degrees 24' S and 50 degrees 17' W), between September, 1998 and August, 1999. Liolaemus occipitalis presented a mean body temperature of 30.89 degrees C (SD = 4.43 degrees C; min = 16.4 degrees C; max = 40.2 degrees C; N = 270), that varied on a daily and seasonal basis according to microhabitat thermal alterations. The substrate temperature was the main heat source for thermoregulation of L. occipitalis as in all seasons of the year it was responsible for the animals' temperature variation (82% of the collected lizards in the spring; 60% in the summer; 84% in the fall and 68% in the winter). The results indicate that L. occipitalis is a saxicolous, thigmothermic and heliothermic species that regulates its body temperature through behavioral mechanisms.