The evolution of Dexiarchia

Heterobranch Gastropoda (Mollusca), comprise a heterogeneous group of predominantly terrestrial forms (Pulmonata), but also with many different marine taxa, including the biggest marine group, the Nudibranchia, with at least 4,000 species. Within the Nudibranchia, two monophyletic subtaxa are generally distinguished: Euctenidiacea (= Anthobranchia) and Dexiarchia (Cladobranchia + Doridoxa). Dexiarchia comprises at least 2,000 species with many additional species still undescribed. Currently, 34 families with nearly 100 different genera are recognized. There exist no phylogenetic analyses of Dexiarchia that comprises all major families and corroborates relationships within this group. We investigate this long standing problem by exploiting transcriptomic data. Resulting phylogenetic hypotheses are forming the base for the investigation of the evolution of this highly diverse group with extraordinary biological phenomena and will help resolving some of the incongruences in our current understanding of marine heterobranch evolution.