US-Germany DDEP: Evolutionary consequences of Cenozoic climate change on African reptile diversification

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Historical climate change is a major driving force shaping diversification patterns of terrestrial vertebrates. While most of this evidence is based on mammals and birds, the evolutionary dynamics of another large group - squamate reptiles (the clade including snakes and lizards) - remain largely unexplored. For this doctoral dissertation enhancement project, the graduate student Christy Hipsley, under the guidance of Dr. Barry Sinervo, will investigate the effects of historical climate change on the evolution of a large family of lizards, the Lacertidae. In collaboration with Dr. Johannes Müller at the Museum für Naturkunde in Berlin, Germany, a comparative phylogenetic approach will be used to test for correlations between ancestral shifts in diversification rates, ecology and morphology in African lacertid lizards. Results will be compared with paleoclimatic data to determine if taxonomic and morphological diversification has been driven by the aridification of Africa since the early Cenozoic, or if there are other factors (e.g., evolutionary age, ecological niche, morphological innovation) that determine species richness in this clade.While tropical rainforests are often viewed as cradles of diversity, this research focuses on the importance of deserts as centers of reptile evolution. Outcomes of this work include a better understanding of causes of variation in rates of molecular evolution, morphological responses to climate change, and the interplay between ecological variables and biodiversity. Research on lacertid lizards in particular will help to fill taxonomic and geographical gaps in the climate impact literature, which will be useful both for comparisons with other terrestrial vertebrates and to understand how animals with very different physiologies (i.e. cold versus warm blooded) respond to climate change. The collaborative nature of this project, spanning the United States, Europe and Africa, also presents a unique opportunity for people from diverse backgrounds to work together on issues surrounding global climate change, which is now a major concern for the future of biodiversity.