Secondary Species Hypothesis (SSHs) corroborated with the <i>psb</i>A gene.

<p>Bayesian gene tree with posterior probabilities (>0.9) next to each node. Branch tips are the 16 <i>psb</i>A haplotypes detected in the study. Numbers at the tip of the branches are Primary Species Hypothesis (PSH) codes (see <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0104073#pone-0104073-g001" target="_blank">Fig. 1</a>) while vertical thick lines delineate SSHs; letters A–D next to some nodes indicate major lineages. Stacked horizontal bars next to the gene tree indicate the morphospecies identified at the onset of the study; numbers within bars are the actual number of specimens recorded for each morphospecies. The distribution of each SSH across OSPAR regions and its taxonomic identity is also provided. * topotype specimens sequenced, ** type specimen sequenced.