The phylogeny of Nudibranchia (Opisthobranchia, Gastropoda, Mollusca) reconstructed by three molecular markers

Abstract The phylogeny of the Nudibranchia and its major constituent taxa is investigated by comparing the complete sequences of the 18S rDNA of 54 species, a part of the 16S rDNA of 38 species and part of cytochrome c oxidase I ( cox1 ) of 45 species. These datasets are analyzed individually and in combination for the subset of taxa where information on all three markers is available. The results are compared to published cladistic analyses based on morphological data. The monophyly of the Nudibranchia and the monophyly of its two major groups, the Anthobranchia/Doridoidea and Cladobranchia, is confirmed. Incongruencies between the molecular and morphological data is discussed, as well as incongruencies between the three molecular markers.