MOLECULAR PHYLOGENY OF CHAETODON (TELEOSTEI: CHAETODONTIDAE) IN THE INDO-WEST PACIFIC: EVOLUTION IN GEMINATE SPECIES PAIRS AND SPECIES GROUPS

Abstract

We present a molecular phylogeny of Chaetodon derived from the analysis of sequences from mitochondrial cytochrome (cyt) b and 12S rRNA genes for 41 ingroup Chaetodon species. One species of Chelmon and one species of Prognathodes were used as outgroups to root the molecular trees. Two different computer software packages were utilized, namely, MEGA 2 and PHYLIP version 3.6a2. Multiple methods such as neighbor-joining (NJ), minimum evolution (ME), maximum likelihood (ML) and maximum parsimony (MP) were used. Cytochrome b sequence data provided greater resolution than 12S rRNA. Of the nine Chaetodon subgenera sampled, all were in the monophyletic group, but their phylogenetic relationships differed significantly from those inferred from morphological characters. Lepidochaetodon was the basal subgenus followed by Exornator and others. Molecular data support that Corallochaetodon and Citharoedus are sister groups, as suggested by morphological analysis. We found no geographical pattern of speciation events in the Indo-West Pacific and speciation occurred throughout the Indo-West Pacific as a result of diverse mechanisms. The evolutionary patterns of species pairs or species groups were more complex than previous envisioned as evidence from estimated divergences between species pairs suggests that the speciation events have occurred many times.