Fig. 4

Example of graphical summarization of mapping results. Evolution of coloniality in scleractinian corals, data from [17]. In both cases, the MAP (maximum a posteriori) tree from a “thinned” posterior distribution of ultrametric trees (obtained using BEAST, n = 302) was used to summarize SFREEMAP’s results. The branch fraction painted with a given tone corresponds to the posterior probability of that tone. Gray branches are not present in other trees. a) Number of transitions from colonial to solitary states. Scale goes from 0 to over 5.34 transitions per branch. Branch coloring follows the same rationale as dwelling time. Note how greater number of transitions (represented by the “greenshift”) are observed on longer branches which, in the framework of stochastic mapping, offer more evolutionary opportunity for state change. b) Dwelling times in colonial state. Color scale goes from 0% (or 100% solitary) to 100% dwelling time on the colonial state. If 80% of a branch is painted pure red, this means that 80% of the trees in the posterior had equivalent branches expected to have been colonial throughout the entire duration of the corresponding lineage. If 80% of a branch is painted in pure green, then 80% of the equivalent branches were expected to have been colonial during half of the lineage duration. Note that coloring shifts to either red (colonial) or blue (solitary) towards the tips of the tree, matching the state observed on the terminals, whereas most of the internal branches closer to the root are green, due the uncertainty associated with increasing internal branch lengths