基于形态和16S rRNA基因的拟相手蟹分类研究

Taxonomic study on the genus Parasesarmabased on the morphology characteristics and mtDNA 16S rRNA gene

拟相手蟹属因其形态极其相似成为相手蟹科分类中最有疑问的一个属。通过对中国沿海近亲拟相手蟹Parasesarma affine、斑点拟相手蟹P.pictum、三栉拟相手蟹P.tripectinis、P.ungulatum及褶痕拟相手蟹P.plicatum5种拟相手蟹的形态对比发现,可从它们的螯足形状（包括螯足掌节背面的梳状栉,可动指背面突起数目）及雄性第一腹肢形状对其进行区分。对其线粒体16SrRNA基因序列进行分子系统发育分析,结果表明5种拟相手蟹之间的遗传距离为1.9%～9.3%,达到了种间差异水平;构建的系统发育树显示近亲拟相手蟹与褶痕拟相手蟹汇聚成一支,随后与P.ungulatum聚在一起,斑点拟相手蟹与三栉拟相手蟹汇聚成独立支系。形态和分子证据均支持5种拟相手蟹分别为独立有效物种。

The taxonomy of the genus Parasesarmais one of the most problematic in the Sesarmidae,with their very similar morphology.We compared the morphology characteristics of Parasesarma affine,P.pictum,P.tripectinis,P.ungulatum（from the coast of China）and P.plicatum（from Singapore）,and found that these five species could be distinguished from the shape of chelipeds（which included pectinate crest of dorsal surface of palm,the number of dactylar tubercles of the chelipeds）and the male first gonopod.The partial sequences of mitochondrial DNA 16 SrRNA gene of these five Parasesarmaspecies were contributed to molecular phylogenetic analysis,and the result showed that the genetic distances was 1.9%～9.3% between interspecies,and had reached the level difference of interspecies;the phylogenetic tree indicated that P.affine and P.plicatum were clustered together and then clustered into a clade with P.ungulatum,P.pictumand P.tripectinis were clustered into a distinct clade.Both of evidence of morphological and molecular data supported that the five Parasesarmaspecies were separate and valid species.