Integrating 3D-microanatomy of selected heterobranch gastropods into molecular phylogenetics

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Molecular systematics provides increasing evidence for the backbone topology of what we call the New Heterobranchia tree. This radically reorganizes roughly 40,000 morphologically and ecologically diverse species, including opisthobranch and pulmonate snails and slugs. However, exact relationships, anatomy and evolution of many major traditional clades,, especially of lower heterobranchs, remained unresolved. In the first period of the present project we have examined representatives of most major heterobranch lineages, adding detailed microanatomical information from serial semithin histological sections of entire individuals. We have also provided multi-locus data and first hypotheses on the origin and evolution of several of the most enigmatic and aberrant major heterobranch clades, such as Rhodopemorpha, Murchisonellidae, Ringiculidae, and some Acteonoidea-related groups. In the prolongation period applied for herein we want to 1) take the chance and examine in 3D microanatomical detail unique material of minute, extremely elusive representatives of Cimidae, Graphidae and Tjaernoeeidae, the last 3 lower heterobranch families without any microanatomical knowledge. In particular, we want to 2) complete our multi-locus data sets, perform state of the art phylogenetic analyses, and reconstruct the evolution of heterobranchs comprehensively. Integrating molecular and morphological evidences will allow for re-evaluating homology and function of organs and their evolution across heterobranchs, leading to a new understanding of this large and important group.