Correlations between habitat use and body shape in a phrynosomatid lizard (Urosaurus ornatus): a population-level analysis

Recent ecomorphological studies have shown that the predicted correlations between morphology and ecology on broad taxonomic levels are often obscured when comparing more closely related groups. Among species, comparisons of lizards often indicate very little support for adaptive radiations into nov el habitats. As few population level studies have been performed, we compar ed body, head and limb shape between four populations of Urosaurus ornatus living in structurally distinct habitats (cliffs, rocks, trees and boulders ). Surprisingly, clear correlations between habitat use and body shape amon g populations were found, most of which were in good accordance with a prio ri biomechanical predictions (e.g. flat body and head for extreme climbers; long distal hindlimb segments for jumpers and runners; narrow body and lon g tail for tree dwelling lizards). This indicates that populations of Urosa urus ornatus are seemingly 'adapted' to the habitat they live in. However, quantification of performance and behaviour are needed to determine the ada ptive nature of these observations. (C) 2001 The Linnean Society of London.