浮游软体动物长角螺属(Clio)种类的分类学和谱系地理学

Taxonomy and phylogeography of Clio species based on mtCOI and 18S rRNA genes

许多终生浮游软体动物接近全球分布或呈环球分布,是海洋酸化和谱系地理学研究的良好材料。本文以西北太平洋和北印度洋的长角螺属(Clio)种类为材料,通过测定其线粒体COI基因(mtCOI,55条)和核18S rRNA基因(9条)序列,结合数据库中已有的序列,对该属进行了分类学和谱系地理学研究。结果表明,矛头长角螺(C. pyramidata)和尖棘长角螺(C. cuspidata)在mtCOI基因系统树中均形成4个明显分化的谱系分支,分别为支系A–D和支系E–H。矛头长角螺的支系A为全球分布,中国海及邻近海域可能仅有支系A的存在,支系B、C和D分布于特定海域。尖棘长角螺也存在明显的谱系地理结构,西北太平洋北赤道流南北两侧存在2个不同的支系,分布于吕宋海峡的支系E为一新的谱系分支。各支系内mtCOI基因的K2P遗传距离在0~0.026之间,支系间的遗传距离在0.031~0.089之间。膨凸长角螺(C. convexa)和曲形长角螺(C. recurva)没有明显的地理遗传分化。18S rRNA基因支持支系D为独立种,但不支持其他支系的划分。矛头长角螺和尖棘长角螺内部可能存在隐存多样性。洋流可能会成为物种扩布和基因交流的障碍。

Many species of holoplanktonic gastropods have a near-cosmopolitan or circumglobal distribution, some of which are used for phylogeography and ocean acidification research. Using mitochondrial COI(mtCOI, 55 animals) and nuclear 18 S rRNA(9 animals) sequence data from specimens sampled from Northwest Pacific and North Indian Oceans, and together with the sequences from GenBank, we investigated the taxonomy and phylogeography of Clio species. Four lineages were defined by mtCOI tree for C. pyramidata(Lineages A–D) and C. cuspidata(LineagesE–H), respectively. Lineage A of C. pyramidata showed a circumglobal distribution, while Lineages B, C and D had their restrained dispersal. Only Lineage A was found in Chinese seas and adjacent waters. The divergent mtCOI lineages of C. cuspidata were also phylogeographical structured. Two distinct lineages(E and F) of C.cuspidata were observed in the Northwestern Pacific, which are distributed in the south and north areas of the North Equatorial Current respectively. The K2 P distances of intra-lineage were between 0 and 0.026, while the distances of inter-lineage ranged from 0.031 to 0.089. Geographic structures were not observed in C. convexa and C. recurva.The morphospecies C. pyramidata and C. cuspidata may harbour cryptic diversity. Our results also suggested that ocean currents may limit the species dispersal and gene flow.