Relationships of marine Haplosclerida (excerpt from larger phylogenetic analyses shown in Fig. 5) and evolution of extension regions. Sketches of predicted secondary structures for extensions and conserved flanking regions correspond to outlined boxes in Fig. 4. Asterisks mark nodes that were found in at least 96% of sampled trees after burn-in in both Bayesian analyses (PHASE and MrBayes, see Material and Methods for details); plus signs mark nodes that appeared in lower frequencies, but still above 84% in one, or both of the analyses. For each species, the family is shown below the sequence name.