Phylogenetic Relationships of Flounders from the Family Pleuronectidae (Ostichties: Pleuronectiformes) Based on 16S rRNA Gene

Abstract

The systematics and phylogeny of flatfish is investigated on the basis of an incomplete nucleotide sequence of 16S rRNA and the complete Co-1 and Cyt-b sequences. In total 62 specimens of 14 species of our own collections were submitted to the GenBank/BOLD repositories and studied. Four types of gene trees were reconstructed: Bayesian (BA), maximum likelihood (ML), minimum evolution (ME), and neighbor joining (NJ). These trees showed basically similar topology. Two separate branches on the trees support the previously identified subfamilies Hippoglossoidinae and Pleuronectinae with the monophyletic status of these taxa. The subfamily Pleuronectinae can be considered monophyletic if the tribe Microstomini is excluded from it and genus Lepidopsetta is moved into the tribe Pleuronectini. Three sets of nucleotide sequences were formed and independently studied. One set included all the obtained 16S rRNA gene sequences (291 bp), the second set included a sample of longer 16S rRNA sequences (617 bp), and the third set consisted of three gene sequences: 16S rRNA, Co-1, and Cyt-b (2926 bp). All three data sets gave a similar phylogenetic signal, which is consistent with the traditional concept of the taxonomy of the Pleuronectiformes order; however, the second and third sets provided better resolution of topology.