| 摘要: |
| 轮螺科（Architectonicidae）是一类成体螺壳右旋而面盘幼虫螺壳左旋的腹足类，其面盘幼虫在国内一直被误定为强卷螺属（Agadina）种类，归在螔螺科（Limacinidae）中。本文基于线粒体16S rRNA基因序列和胚壳的形态特征，对轮螺科面盘幼虫进行了物种鉴定。结果表明，根据胚壳壳顶和脐孔的形态特征，面盘幼虫可大致分为2种明显不同的形态类型：形态类型I的个体壳扁，壳顶凹陷，脐孔形状规则，圆而深；形态类型Ⅱ的个体壳顶突出，脐孔形状不规则，浅或深，肛区龙骨有或无。GMYC（Generalized Mixed Yule Coalescent）和ABGD（Automatic Barcoding Gap Discovery）分析显示，轮螺科面盘幼虫16S rRNA基因的50种单倍型形成19个分子可操作分类单元（molecular operational taxonomic units，MOTUs），同一MOTU的幼虫具有相同的胚壳形态。其中，11个MOTUs中的幼虫属于形态类型I，8个MOTUs中的幼虫属于形态类型Ⅱ。此外，不同MOTUs的面盘幼虫，其软体部黑色幼体器官（Black Larval Organ）的位置和大小也不同。根据研究结果推测，轮螺面盘幼虫的形态具有种或属特异性。轮螺科面盘幼虫单倍型形成的MOTU数量明显多于国内目前已记录的物种数，其种类多样性可能被低估。基于16S rRNA序列能直接鉴定到种的仅Psilaxis radiatus和配景轮螺（Architectonica perspectiva）2种。本文也从分子水平订正了国内长期以来的分类错误。 |
| 关键词: 轮螺科(Architectonicidae) 面盘幼虫 形态学 16S rRNA基因 物种鉴定 |
| DOI：10.11693/hyhz20180700166 |
| 分类号:Q959.212 |
| 基金项目:国家自然科学基金，41606191号；国家海洋局南海分局局长基金，1705号。 |
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| SPECIES IDENTIFICATION OF ARCHITECTONICID VELIGER LARVAE BASED ON MORPHOLOGICAL AND MITOCHONDRIAL 16S rRNA GENE |
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LI Hai-Tao, ZHOU Peng, HE Jing, HUANG Bin-Bin, CHEN Kai-Biao
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South China Sea Environmental Monitoring Center, State Oceanic Administration, Guangzhou 510300, China
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| Abstract: |
| Species of the family Architectonicidae are a group of gastropods that shells of adults are dextral but the protoconchs of veliger larvae are sinistral. The architectonicid veliger larvae have been mis-identified as Agadina species (Limacinidae) for more than a half century in China due to their sinistral shells. In this study, we analyzed the protoconch morphological characteristics of veliger larvae and sequenced the partial mitochondrial 16S rRNA gene from 66 veliger larvae and three adults of Architectonicidae to clarify the taxonomic debate. The veliger larvae can be divided into two morphotypes in morphology. The protoconchs of morphotype I are characterized by the sunk apex and the round and deep umbilicus. The protoconchs of morphotype Ⅱ are distinguished from those of morphotype I by their raised apex and retuse umbilicus. The 50 haplotypes derived from the 16S rRNA gene were grouped into 19 distinct molecular operational taxonomic units (MOTUs) using GMYC and ABGD analyses. Larvae of morphotype I could be assigned into 11 MOTUs, while the 8 remaining MOTUs had shell characteristics of morphotype Ⅱ. The position and size of black larval organs are also distinct among different MOTUs. These results suggest that the morphological characteristics of shells and black larval organs are valuable for species and/or genus recognition. However, only a few haplotypes were identified to the species level because of the insufficient reference sequences in GenBank, and the biodiversity of Architectonicidae could be underestimated in China. |
| Key words: Architectonicidae veliger larvae morphology 16S rRNA gene species identification |
