伶鼬榧螺（Oliva mustelina）的分子鉴定及其形态变异

摘要

根据榧螺螺旋部的差异可将其分为两种不同的形态类型，类型Ⅰ（MorphotypeⅠ）的个体螺旋部陷入体螺层中，其壳顶与前部数螺层愈合；类型Ⅱ（Morphotype Ⅱ）的个体螺旋部高出壳顶，缝合线明显，此类型可明确鉴定为伶鼬榧螺（Oliva mustelina ）。本研究通过线粒体 COⅠ和16S rRNA 基因序列的分析对两种形态类型的榧螺进行了分子鉴定。结果表明：两种形态类型的榧螺含有共享的单倍型；不同形态类型间的遗传距离和同一形态类型内的遗传距离重叠；两者的单系性在系统发育分析中没有得到显现，而是共同构成一个单系。因此，两种形态类型的个体均为伶鼬榧螺。类型Ⅰ可能是伶鼬榧螺中一种少见的有别于典型个体的形态变异类型。%Based on the morphologic difference of spire,Oliva snails with similar shell colors and patterns can be di-vided into two morphotypes.MorphotypeⅠis characterized by the sunk spire in its concavity below the shoulder of the body whorl and the whorls of spire fused together.MorphotypeⅡshows the identical conchological characteris-tics of typical specimens of O.mustelina.The mitochondrial cytochrome c oxidase subunitⅠ(COⅠ)and 16S rRNA gene segments of these two morphotypes were sequenced.Genetic analyses clearly showed many common haplo-types and lack of significant genetic differentiation between the two morphotypes.In addition,further phylogenetic analyses showed that all haplotypes were grouped in a monophyletic clade.Thus,the two morphotypes are not ge-netically diagnosable,and therefore should be assigned to species O.mustelina.MorphotypeⅠmay be a new form of O.mustelina that differ from the typical specimens.