Abstract
Recently, it has become possible to understand the evolution of diversity of biological form at all levels. Progress in comparative developmental genetics has helped to explain differences in body structure, whereas molecular phylogenetics and evolutionary ecology target the evolution of those differences. For well-known taxa, this allows the creation of a comprehensive "evo-devo" image of the evolutionary history and dynamics of a certain branch within the Tree of Life. In the present project, such an approach is applied to understand morphological diversity in a group of bizarrely-shaped microsnails. The species of the genus Opisthostoma coil in highly irregular ways, and show shell shapes that carry such ornaments as spines, ribs, and flanges. Earlier studies by the research group have shown that this diversity of form is driven partly by evolutionary arms races with predators. Here, we aim to test this hypothesis more broadly and deeply with field experiments, while simultaneously, the evolution of shell traits is traced within a molecular-phylogenetic framework. Pattern and process are unified by a computer model in which, based on knowledge of mollusc developmental genetics and Raup's algorithms for describing shell coiling, the evolution of novel shell shapes is simulated. Hence, the project makes full use of the advantages of shelled molluscs as model organisms, namely: a morphogenesis that can be modeled relatively simply, as well as the possibility to measure selection pressures in the field.