Diversification in space and time across land and sea - a land snail genus conquering continents and islands

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Oceanic islands have played an important role in understanding evolution. The Canary Islands offer exceptional preconditions to study diversification and speciation because of their habitat diversity and well documented geological history. Based on molecular data, we will study the diversification of the land snail genus Theba, which has its centre of diversity on the Canary Islands, but most likely originated in North West Africa, where five of the 14 recent species occur. In general, snails tend to preserve distribution patterns over longer periods of time due to their limited potential for dispersal, but Theba represents a particularly interesting case for studies of speciation. There is an excellent fossil record on the islands, which will complement the inferences based on the phylogenetic analyses of the extant species. In combination, molecular, paleontological and morphometric data will serve to estimate evolutionary rates on both the molecular and the morphological level. The distribution on the continent and the Canary Islands provides an ideal distributional contrast providing different settings for diversification, and species and putative subspecies occur in allo-, para- or sympatry allowing to test different scenarios of diversification. Theba thus is an exciting, new model system promising exceptionally deep insights in evolutionary processes from an empirical point of view.