Molekulare Phylogenie und Biogeographie der Chamäleons

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Chameleons are a group of lizards characterized by various unique and spectacular morphological features. They also are an appropriate model with which to decipher biogeographic questions such as the relative importance of dispersal or vicariance in the origin of the biota on landmasses in the Indian Ocean. Due to their presumed (and partly demonstrated) low vagility, chameleons can also serve to analyse biogeographic patterns and processes on small scales. For such analyses, a wellresolved and taxon-rich phylogenetic hypothesis is a basic requirement. Yet, so far the published phylogenetic studies for these organisms suffer from low resolution, especially among basal branches, and from incomplete taxon coverage. The project proposed here will carry out a multilocus molecular phylogenetic analysis of chameleons, based on DNA sequences from multiple nuclear and mitochondrial genes, with a dense taxon sampling of at least 80% of all chameleon species. The phylogeny obtained will be dated using Bayesian molecular clock methods and will be used to test competing biogeographic scenarios. In concert with available georeferenced databases of chameleon distribution, we will identify geographic hotspots of chameleon species richness, endemism, and phylogenetic diversity. These patterns will be used to reconstruct historical diversification processes of chameleons, and to infer geographic priorities for nature conservation.