珠蚌科六种蚌的钩介幼虫形态比较研究

COMPARATIVE STUDIES ON MORPHOLOGY OF THE GLOCHIDIA OF SIX MUSSEL SPECIES(MOLLUSCA:UNIONIDAE)

本文观察了背角无齿蚌、沼纹冠蚌、剑状矛蚌、圆顶珠蚌、刻裂丽蚌和洞穴丽蚌等６种蚌的育儿囊类型；用光镜和扫描电镜观察和研究了幼虫的形态特征。结果表明，前４种蚌的育儿囊属外鳃类的同生型，后２种的育儿囊属外鳃类的四生型；６种幼虫均为钩介幼虫，其中前４种为有钩型，后２种为无钩型；６种幼虫的大小、形态有别，并证明种间幼虫的壳钧和壳饰的亚显微形态显然有异。本文还就６种蚌在Ｓｉｍｐｓｏｎ分类系统中的地位与按它们的育儿囊和钩介幼虫类型得到的归类进行比较。结果表明，Ｓｉｍｐｓｏｎ对６种蚌中３种的分类与归类不妥。本文为研究我国淡水贝类的分类提供一条新的途径，并为建立珠蚌类的自然分类系统积累资料。

The marsupia and glochidia of Six freshwater mussel species,Anodonta woodianawoodiana,Cristaria plicata, Lanceolaria gladiola, Unio douglasiae, Lamprotula scripta and L. caveata were studied morphologically.The marsupia onhese specics of mussels are allexobranchial,and further the marsupia of the former four species are homogenial andthe latter two tetragenial.The size of the glochidia varies considerably in relation to theirspecies identity.Furthermore,glochidia of all the former four species are hooked on theirshells,but may be distinguished from each other by the morphology of their shell hooks.However,glochidia of the latter two species are unhooked,with structures similar to thefunctions of the shell hooks.For L. scripta,a spine was observed in the middle of theventral margin of each shell,whilst for L. caveata,a suctorial structure observed in clozeto the ventral margin of the shells.It was therefore indicated that types of marsupia andglochidia,and mopohology of glochidial shell hooks can be used together as diagnosticcharacters in the classification of bivalves.