Fig. 2.
The 50% majority rule consensus phylogram of the stationary trees obtained from the Bayesian inference analysis of concatenated neutral nuclear genes at four-fold degenerate sites mid-point rooted between the two major clades previously identified. Branch support values are the BI posterior probabilities (PP), MP bootstrap (BSMP) and ML bootstrap (BSML) for genes rejecting evidence of positive selection. Branches leading to deep water species are colored in purple. The branch leading to S. droebachiensis is colored blue, as this species occurs primarily in shallow water but can range to a depth of 300 m. Adult depth range: s, shallow (0-50 m); m, medium (0-200 m); d, deep (0-1600 m). Distributions: West Pacific (WP), East Pacific (EP), holarctic (HA). The cross-section of the ultrastructure of primary spines [59]: rectangular (r), trapezoid (z), triangular (t) or ansiform (a)