Is Evolution Predictable? Evolutionary Relationships of Divergence in Ecology, Performance and Morphology in Old and New World Lizard Radiations

A central question in evolutionary biology concerns whether the direction of evolution proceeds in the same manner for groups of species from independent radiations. We investigated this general issue by examining two diverse lizard clades: Caribbean Anolis lizards and lizards from the family Lacertidae. Specifically, we asked: (1) For 13 Caribbean Anolis and 11 lacertid lizard species, whether divergence in habitat use is associated with divergence in morphology and performance, and whether the same associations are found in the two radiations. (2) For 46 species from both groups (92 species in all), do both groups show similar levels of variation in external morphology? In lacertid lizards, there is an evolutionary relationship between divergence in performance and habitat use, and between morphology and performance. By contrast, Anolis lizards show significant correlations between morphology and performance, and between morphology and habitat use. Morphological comparisons show that these differential relationships might be a consequence of differences in the degree of morphological divergence. Although, the mean evolutionary divergence in morphology is very similar for both groups, the anoles show a higher variance in external morphology. These findings suggest that one cannot assume that divergence in habitat use is associated with evolutionary divergence in morphology and performance in the same manner for different groups. Key words: adaptive radiation; ecology; performance; morphology; lizards