Dissertation Research: Evolutionary Ecology and Molecular Phylogenetics of the Lizard Genus Liolaemus

Washington University, Saint Louis MO

Investigators

Abstract

0071337 Losos and Schulte The lizard genus Liolaemus (in the family Iguanidae) contains over 160 species, exhibiting great diversity in ecology, morphology, and life-history. Species are widely distributed throughout the southern half of South America and are the most prominent component of the reptile communities in many areas. In this project, graduate student James Schulte, under the direction of Drs. Jonathan Losos and Allan Larson, proposes to investigate whether species of Liolaemus living in different geographic regions but with similar ecological conditions evolve similar body shapes. More specifically, groups of species in Argentina and Chile living in ecologically similar areas (semi-arid zone and rocky transition zone) will be compared to identify whether the body sizes and habitat occupation of species in one group match the body sizes and habitat occupation of the species in the corresponding group from the other area. Observations on ecology for the several sympatric species in each of the four study sites, combined with morphometric analyses of body size and shape, provide the evidence for adaptation to local habitats. Also, the genealogy among species will have to be taken into account to exclude the possibility that similar body shape and habitat use are the result of species being closely related phylogenetically, and not the result of adaptive convergence to similar environmental conditions. The genealogy will be inferred from DNA sequences of the mitochondrial genome spanning over 1700 base pairs and 12 gene regions. Results from this project will greatly improve our understanding of the phylogenetic relationships within the second-largest lizard genus in the world, serve as an excellent comparison to previous work on other biological assemblages, and explore the reasons why animals and plants living in ecologically similar areas evolve similar features.