Maximum likelihood tree of the major deuterostome groups excluding tunicates using the amino acid sequences of all thirteen mitochondrial protein-coding genes. The numbers on the nodes show the bootstrap percentages (BP) for ML and the posterior probabilities (PP) of the Bayesian analyses in this order. Asterisks indicate highest support values. The numbers in parenthesis behind the deuterostome groups show the number of analyzed species. The length of the triangles for each group indicates the variability within the group. The extreme long branch leading to the pterobranch R. compacta is based on its highly different protein-composition compared to other deuterostome sequences (for details see text).