Phylogenetic relationships among major gastropod lineages. Note that Heterobranchia additionally to Opisthobranchia and Pulmonata comprises some minor groups (Valvatoidea, Rissoelloidea, Architectonicoidea, and Pyramidelloidea). (A) Morphological phylogenies of Haszprunar  and Ponder and Lindberg . (B) Molecular analysis based on genomic DNA by McArthur and Harasewych , and combined analysis of molecular and morphological data by Aktipis et al. . (C) Molecular phylogeny based on mitochondrial genome arrangements by Grande et al. ; Note that neritimorph gastropods were not included in the analysis.