两种眉足蟹科蟹类的形态特征与遗传多样性研究

THE MORPHOLOGICAL CHARACTERS AND GENETIC DIVERSITY OF BLEPHARIPODA LIBERATE SHEN AND LOPHOMASTIX JAPONICA

研究描述了解放眉足蟹和日本冠鞭蟹的形态特征,并基于线粒体COⅠ基因片段分析了解放眉足蟹和日本冠鞭蟹的遗传多样性现状。解放眉足蟹的主要形态特征为体白色,甲壳呈琵琶形,背部中线隆起,表面较光滑,步足扁平,指节弯曲明显;日本冠鞭蟹的主要形态特征为体红褐色,甲壳呈卵形,头胸甲长大于甲宽,有许多白色斑点,步足简化成铲,上有刚毛。在长度为659 bp的线粒体COⅠ基因片段上,解放眉足蟹20个个体共检测到15个单倍型,平均GC含量为33.26%,单倍型多样度为0.9421,核苷酸多样度为0.0059;日本冠鞭蟹20个个体共检测到15个单倍型,平均GC含量为47.65%,单倍型多样度为0.9415,核苷酸多样度为0.0061。基于K-2P模型计算得到解放眉足蟹和日本冠鞭蟹种间遗传距离为0.2705,解放眉足蟹个体间平均遗传距离为0.006,日本冠鞭蟹个体间平均遗传距离为0.006,种间遗传距离显著大于种内遗传距离。以Emerita emeritus为外群构建系统树,不同蝉蟹分别形成各自独立的分支,表明COⅠ基因可以作为蝉蟹DNA条形码辅助分类。

The present study described the morphological characters of Blepharipoda liberate and Lopoomastix japonica, and analyzed the genetic diversity of two species based on COⅠ gene. The diagnostic characters of B. liberate are as following： Carapace approximately 1.3 times longer than wide; strongly keeled medially; anterior margin with large rugosi spine on either side of ocular sinus; frontal region smooth with few low teeth posterior to rostrum. The diagnostic characters of L. japonica are as following： Carapace approximately 1.2 times longer than wide; gently keeled medially; anterior margin with proximally broad and distally narrowing rugose outer-ocular spines on either side of ocular sinus, concave medially. The gene diversity and nucleotide diversity of B. liberate based on COⅠ gene were0.942±0.043 and 0.0059±0.0034, respectively. The gene diversity and the nucleotide diversity of L. japonica were0.941±0.0048 and 0.0061±0.0035, respectively. The K-2P distance was 0.2705 between the B. liberate and L. japonica,and these two species were distributed into two distinct branches based on neighbor-joining tree analysis, which reinforces the validity of DNA barcoding on classification of Blepharipodidae based on COⅠ gene.