Evolutionary correlations between microhabitat specialisation and locomotor capabilities in the lizard genus Niveoscincus

The evolutionary consequences of generalised versus specialised habit is a central issue in organismal biology. Theory predicts that specialist species may have greater capabilities than generalist species in particular habitats but will not be able to maintain this excellence across a broad range of habitats. The evolutionary consequences of ecological specialisation, in terms of functional capabilities, were investigated in the lizard genus Niveoscincus from Tasmania. Breadth of microhabitat occupation and ecologically relevant locomotor capabilities were quantified across the genus. Laboratory performance trials demonstrated that some species excelled in just a few of the five performance traits measured, while other species performed well at all traits but did not excel at any. Results of comparative analyses demonstrate that there is a significant evolutionary correlation between microhabitat breadth and range of locomotor capabilities. These results provide convincing evidence that habitat specialists have a correspondingly limited range of locomotor capabilities.