CARTER, T.L.*; ERICKSON, L.B.; ELLIOTT, J.K.: The influence of hybridization on anemonefish evolution

Anemonefishes (Genera:Amphiprion and Premnas; Family Pomacentridae) are a group of 28 species of coral reef fishes that are obligate symbionts of large tropical sea anemones. A recent molecular phylogenetic study of anemonefishes, based on data from two mitochondrial genes (cyt b and 16S) for six representative species, produced a phylogeny that was significantly different from a previous phylogeny based on morphological data. To further evaluate this difference, we have sequenced another mitochondrial gene (ND2) and a nuclear gene (Tmo-4C4) for 14 species of anemonefishes. The phylogeny based on mitochondrial data was significantly different from the phylogeny based on nuclear data. Because mitchondrial DNA is maternally inherited, phylogenies based on mitochondrial data can be misleading if hybridization among species has occurred. At least one anemonefish species (Amphiprion leucokranos) is thought to be the result of hybridization between two very different anemonefish species (A. chrysopterus and A. sandaracinos). Both our mitochondrial and nuclear data provide molecular evidence for the hybrid origin of A. leucokranos. The nuclear data also indicate that other anemonefish species may be the result of past hybridization events. This suggests that hybridization may have been important in anemonefish speciation and that reticulate evolution is a plausible explanation for the diversification patterns observed in this group of coral reef fishes.