A new record of Sebastes koreanus from China based on morphological characters and DNA barcoding

A new record of Sebastes koreanus （Kim and Lee, 1994） was documented based on morphological characters and DNA barcoding. Fifty-six Sebastes specimens were collected from the coastal waters of northern China. Samples were identified as S. koreanus based on morphological characters. The coloration and morphometric measurements were consistent with those described from specimens collected in South Korea. In this study, specimens had the following morphological characteristics： light brown body with dark stripes and tiny dark spots, 4-5 wide indistinct vertical patterns on the side, 2 radial stripes behind and below the eyes, 1 large dark blotch on the opercle. Additionally, the following meristie characters were recorded： dorsal fin XIV-13, pectoral fin 16, anal fin III-6-7, pelvic fin [-5, lateral line scales 29-30, and vertebrae 26. The fragment of cytochrome oxidase subunit I （CO1） gene of mitochondrial DNA was sequenced for phylogenetic analysis. The mean genetic distance within the species was 0.3%. Net genetic distances between S. koreanus and other Sebastes species ranged from 3.1% to 7.6%, which was greater than the threshold for species delimitation. The phylogenetic analysis strongly supports the validity of S. koreanus in China at the genetic level. The origion, evolution, patterns of speciation and unique features in genome divergence among primate lineages of this species still need future directions of research.

Molecular phylogeny and evolution of Scomber(Teleostei:Scombridae)based on mitochondrial and nuclear DNA sequences

A molecular phylogenetic analysis of the genus Scomber was conducted based on mitochondrial(COI,Cyt b and control region) and nuclear(5S rDNA) DNA sequence data in multigene perspective.A variety of phylogenetic analytic methods were used to clarify the current taxonomic classification and to assess phylogenetic relationships and the evolutionary history of this genus.The present study produced a well-resolved phylogeny that strongly supported the monophyly of Scomber.We confirmed that S.japonicus and S.colias were genetically distinct.Although morphologically and ecologically similar to S.colias,the molecular data showed that S.japonicus has a greater molecular affinity with S.australasicus,which conflicts with the traditional taxonomy.This phylogenetic pattern was corroborated by the mtDNA data,but incompletely by the nuclear DNA data.Phylogenetic concordance between the mitochondrial and nuclear DNA regions for the basal nodes supports an Atlantic origin for Scomber.The present-day geographic ranges of the species were compared with the resultant molecular phylogeny derived from partition Bayesian analyses of the combined data sets to evaluate possible dispersal routes of the genus.The present-day geographic distribution of Scomber species might be best ascribed to multiple dispersal events.In addition,our results suggest that phylogenies derived from multiple genes and long sequences exhibited improved phylogenetic resolution,from which we conclude that the phylogenetic reconstruction is a reliable representation of the evolutionary history of Scomber.