Phylogeny of the chaetodontids on the basis of kidney and intestinal differentiations

The chaetodontid kidneys and intestinal coiling patterns were classified. Morphological variations of these systems were analyzed to elucidate the chaetodontid phylogenies. The present data suggest that (I) all chaetodontids (not including pomacanthids, Mierocanthus, and Vinculum) share a common ancestor; (2) except for Forcipiger, Hemitaurichthys, Heniochus, and Johnrandallia, the rest of the chaetodontids form a monophyletic group; (3) Chelmon and Chelmonops are closely related groups; (4) within the monophyletic group including Chaetodon and Parachaetodon, Parachaetodon, Prognathodes series of the genus Chaetodon, and some Chaetodon species are more closely related to each other than to other Chaetodon species; (5) the similarity in kidney morphology among Forcipiger, Hemitaurichthys, Heniochus, and Johnrandallia provides no strong evidence for their monophyly. The proposed chaetodontid phylogeny was compared to previously hypothesized phylogenies.