Table_3_Mitogenomic phylogeny of Cypraeidae (Gastropoda: Mesogastropoda).docx

Cowries (Family Cypraeidae) are widely distributed in tropical and subtropical seas, with the highest diversity of cowries in the Indo-Pacific region. However, the classification of Cypraeidae, especially at the lower taxonomic levels, is still controversial. In the present study, we determined the complete mitochondrial genomes of 10 cowries. All the newly sequenced mtDNA encode 13 protein-coding genes (PCGs), 22 transfer RNA (tRNA) genes, two ribosomal RNA (rRNA) genes, and several non-coding regions. The reconstructed mitogenomic phylogeny of Cypraeidae recognized two monophyletic clades, with the first clade comprised of Erroneinae, Cypraeinae and Luriinae and the second clade formed by the single subfamily Erosarinae. The congeneric genetic distance values fall within 0.118–0.144, lower than those above genus level ranging from 0.163 to 0.271, consistent with the current division of genera within Cypraeidae. The divergence time estimated here indicated that the ancestor of Indo-Pacific cowries diversified during the Paleocene, and the closure of the Tethys Seaway might lead to the speciation events of several Indo-Pacific species. This study suggests that the complete mtDNA is a promising tool to improve the phylogenetic resolution of Cypraeidae, and mtDNA could also provide important information for future species delimitation especially within the cowries that possess different morphological phenotypes.

宝螺科（Cypraeidae）物种广泛分布于热带与亚热带海域，印度-太平洋区域的宝螺多样性最为丰富。然而，宝螺科的分类系统，尤其是低阶分类阶元的划分，仍存在较大争议。本研究测定了10种宝螺的完整线粒体基因组，所有新测序的线粒体DNA（mtDNA）均编码13个蛋白质编码基因（PCGs）、22个转运RNA（tRNA）基因、2个核糖体RNA（rRNA）基因以及若干非编码区域。本研究构建的宝螺科线粒体基因组系统发育树识别出两个单系支：第一支涵盖拟枣贝亚科（Erroneinae）、宝螺亚科（Cypraeinae）与露齿宝螺亚科（Luriinae）；第二支仅包含焦掌贝亚科（Erosarinae）一个亚科。同属间的遗传距离介于0.118~0.144之间，低于属间水平的0.163~0.271，这与当前宝螺科的属级划分结果一致。本次研究估算的分化时间显示，印度-太平洋宝螺的祖先类群于古新世发生分化，特提斯海道（Tethys Seaway）的闭合可能促成了若干印度-太平洋宝螺物种的形成事件。本研究表明，完整线粒体基因组可作为提升宝螺科系统发育分辨率的有效工具，同时也可为后续的物种界定（尤其是针对具有不同形态表型的宝螺类群）提供重要依据。