Evolutionary relationships between morphology, performance and habitat openness in the lizard genusNiveoscincus (Scincidae: Lygosominae)

Abstract

Correlations between an animal's morphology and ecological parameters such as habitat characteristics emphasize the intimate link between phenotype and the environment, but are often difficult to interpret because the functional consequences of morphological variation are frequently unknown. We provide one of the few studies relating limb morphology, functional capabilities, and habitat in reptiles. We tested the hypothesis that species occupying open microhabitats would possess relatively longer limbs and faster sprint speeds than those occurring in more closed microhabitats. A number of morphological characteristics relevant to locomotion were quantified, including the length of the bones of the fore- and hindlimbs and body size. A phylogenetic analysis was then used to examine the evolutionary relationships between morphology, locomotor performance and microhabitat openness in seven species of Niveoscincus and one species of the closely related genusPseudemoia . A significant evolutionary relationship was established between sprinting ability, morphology, and the openness of the microhabitat occupied by a species. The phylogenetic analysis demonstrated an evolutionary trend inNiveoscincus of species occupying open microhabitats (e.g. N. greeni, N. ocellatus) being large with long limbs and high sprinting ability, while those occupying closed microhabitats (e.g. N. coventryi, P. entrecasteauxii) are smaller with short limbs and much slower maximum sprint speeds.