Abstract
A close relationship between morphology and habitat is well documented
for anoline lizards. To test the generality of this relationship
in lizards, snout-vent, tail, and limb lengths of 18 species of Tropidurus
(Tropiduridae) were measured, and comparisons made between body proportions
and substrate usage. Phylogenetic analysis of covariance by computer
simulation suggests that the three species inhabiting sandy soils have
relatively longer feet than do other species. Phylogenetic ANCOVA
also demonstrates that the three species inhabiting tree canopies and locomoting
on small branches have short tails and hind limbs. These three species
constitute a single subclade within the overall Tropidurus phylogeny,
and analyses with independent contrasts indicate that divergence in relative
tail and hind limb length has been rapid since they split from their sister
clade. Being restricted to a single subclade, the difference in body
proportions could logically be interpreted as either an adaptation to the
clade's lifestyle or simply a non-adaptive synapomorphy for this lineage.
Nevertheless, previous comparative studies of another clade of lizards
(Anolis) as well as experimental studies of Sceloporus lizards
sprinting on rods of different diameters support the adaptive interpretation.