Fig. 6

Ancestral state reconstruction analysis for the presence of kleptocnides and a distal sac branching off of the digestive gland. Pie charts on the nodes are scaled marginal likelihoods calculated using the ace function in APE. The red boxes indicate: the node at the base of Aeolidida and the genus Hancockia, the two groups in which nematocyst sequestration evolved. The grey box indicates the base of the clade containing Aeolidida and Charcotia, Dirona, and Janolus, which may be where distal sacs originated. Also highlighted with blue background boxes are additional genera within Aeolidida where losses and/or re-gains may have occurred