Meeting Abstract

94.1  Thursday, Jan. 7  Variation in scale counts and body size in Sceloporus lizards in relation to latitude, temperature, and precipitation: a phylogenetic perspective OUFIERO, C.E.*; ADOLPH, S.C.; GARTNER, G.E.A.; GARLAND, T.; Univ. of California, Riverside; Harvey Mudd College; Univ. of California, Riverside; Univ. of California, Riverside coufi001@student.ucr.edu

Variation in physical aspects of the environment often leads to natural selection. Several phenotypic traits have been proposed to vary along a latitudinal/environmental gradient in squamate reptiles. In particular, body size has been proposed to decrease with increasing latitude and thus decreasing temperature at the intraspecific level; similarly, scale counts have been proposed to increase as latitude increases and temperature decreases. Previously, we examined the variation in body size and dorsal scale counts in relation to latitude among 106 species and populations of Sceloporus. We found support for the hypothesis that more/smaller scales are found at higher latitudes, and no support for the relationship between body size and latitude. Here, we re-analyze the data including environmental information, using both conventional and phylogenetic statistical analyses to examine dorsal scale counts and body size in relation to midpoint latitude, temperature, precipitation, and an aridity index (Q). Results suggest that body size increases with increasing mean and maximum temperatures, but not with latitude per se. Our results also suggest that although scale counts increase with latitude, they are significantly negatively related to minimum temperature, precipitation, and Q. Furthermore, the best overall fit model (based on AIC) included total precipitation as a predictor of scale counts. These results suggest that scale size and number variation may be important for such physiological processes as water loss.