ML analyses with a modified taxon sampling. A: The heterobranchs are here represented by representatives of the fast evolving Aeolidina, only. All other taxa are identical to the sampling shown in figure 3, but we excluded also Patellogastropoda. B: Same alignment as used in the inference for figure 3 but excluding all other gastropods except Patellogastropoda. Both analyses were conducted on ten different starting trees with a partitioned GTR + and S16 substitution model and enabling the bootstopping criterium in RAxML (-# autoFC).