Fig. 1

Phylogeny of nine species of strongylocentrotid urchins examined in the present study (reproduced from [44]). The species tree was generated from four-fold degenerate sites from 2301 concatenated genes not exhibiting positive selection. Bayesian, maximum-likelihood, and maximum parsimony trees produced identical topologies. Next to each species is information on their distributions (CIR = Circumpolar, NWP = North West Pacific, NEP = North East Pacific) and adult depth ranges [S = Shallow (0–50 m), M = Medium (0–200 m), D = Deep (0–1600 m)]