Figure 1.

(a,b) Hypotheses for the internal relationships of Gastropoda. Not all listed studies find monophyly of all taxa, as Vetigastropoda is often paraphyletic or diphyletic in earlier studies. Apogastropoda (i.e. Caenogastropoda + Heterobranchia) is monophyletic in nearly all published studies. Hypotheses on the left do not have support from the analyses presented here. Hypotheses on the right are consistent with the analyses presented here and differ only in their rooting. Matrix construction (ABA, OMA), subsampling strategy (1,2,3) and inference method (Bayes, ML) supporting each of these hypotheses is indicated.