SCALING OF LIMB PROPORTIONS IN MONITOR LIZARDS (SQUAMATA, VARANIDAE)

The lengths and diameters of the limb segments of 105 monitor lizards from 22 species were measured on preserved museum specimens in order t o determine whether limb proportions vary in relation to snout-vent le ngth (used as an indicator of overall body size). Scaling exponents (s lopes of allometric equations) were estimated for log-transformed spec ies' mean values, using both conventional nonphylogenetic statistics a s well as the method of phylogenetically independent contrasts. Both m ethods gave essentially the same results. All limb segment lengths and diameters scale with exponents exceeding 1.0; thus, larger species of monitors tend to have larger limbs relative to their snout-vent lengt h. Foot length, however, decreases relative to total hindlimb length i n larger species. Measures of limb segment diameters scale with greate r exponents than do limb lengths; thus, larger species also tend to ha ve relatively thicker limbs. The empirical results on limb shape are c onsistent with predictions derived from biomechanical models.