Fig. 1.

Time-calibrated phylogenetic tree of eight blind (dark purple) and six sighted (light green) crayfish species (Stern et al. 2017). The root was dated to $65$ million years before the present (Stern et al. 2017), but the tree was rescaled to unit height for the analyses. The “sight” design (dark purple and light green squares) matches with the biological vision status of the species studied (Stern and Crandall 2018a). The “block” and “alt” designs (light pink and gray squares) are artificial extreme scenarios representing, respectively, a situation where the design is almost un-distinguishable from the phylogeny-induced grouping (block), and a situation where groups are distributed evenly on the tree to maximize the contrast between sister species (alt).