Systematics of Perca Species Based on Multivariate Morphometrics and Mitochondrial Cytochrome b Gene Variation Analysis

This paper investigated the classification of the genus Perca based on the 32 multivariate morphometrics and the 1 134 bp sequences of mitochondrial cytochrome b (Cyt b) gene. The result of multivariate morphometric analyses showed that the distance between P. fluviatilis and P. schrenki, between P. schrenki and P. flavescens, between P. fluviatilis and P. flavescens was 0.15, 0.14, 0.09, respectively. Perca fluviatilis and P. flavescens were much more similar in morphology, and there was a remarkable difference between P. schrenki and the two other species. In the scatter-plot figure based on principal components 1 to 2, there was an overlapping section between P. fluviatilis and P. flavescens, but there was no overlapping section between P. schrenki and the two others. In the analysis of mitochondrial cytchrome b gene, the percentage nucleotide sequence divergence between P. fluviatilis and P. schrenki, between P. schrenki and P. flavescens, between P. fluviatilis and P. flavescens was 13.08%, 10.68%, 11.47% respectively. The sequence divergences among the three Perca species were within interspecific divergence. Molecular phylogenetic trees were constructed based on the sequences of 20 samples with maximum parsimony (MP), neighbor-joining (NJ) and Maximum likelihood methods. The topological structures of the three trees were consistent, and they all showed that the relationship between the P. schrenki and P. flavescens was much closer than that between P. fluviatilis and P. flavescens. From the genetic divergence of the Cyt b gene and the isolation in geographic distribution, we further concluded that P. fluviatilis and P. flavescens were different species. The genus Perca therefore, includes three species, P. fluviatilis, P.schrenki and P. flavescens.