Molecular phylogeny of familiar flatfish species(Pleuronectidae) in the northwestern Pacific Ocean based on mitochondrial cytochrome oxidase I gene

A molecular phylogenetic analysis was undertaken to evaluate the present systematic status of commercially familiar Pleuronectidae fishes in the northwestern Pacific Ocean.We sequenced a 529 bp fragment of the mitochondrial DNA (mtDNA) COI gene from 34 individuals of these familiar flatfishes from 11 species of nine genera collected in China and Japan.Genetic relationships among haplotypes of specimens from 11 species for COI gene data were reconstructed using the neighbour-joining method and the maximum parsimony (MP) method.The resulting molecular phylogeny of the 11 species, with a few exceptions, supported the existing taxonomy which was based largely on the morphological characteristics.The most noteworthy findings were that the genus Pleuronichthys diverged before deriving of the common ancestor for the other species; the stone flounder, Kareius biocoloratus, should belong to the genus Platichthys with the latin name Platichthys biocoloratus and the genus Verasper was not the extraordinary differentiation from the other species in family Pleuronectidae.The resultant phylogenetic trees were also consistent with multiple origins of direct development within family Pleuronectidae.New proof not only for further illuminating the multiple origins of Pleuronectidae but also for confirmation of the evolutionary relationships among groups in the family will be supported.