两种石龙子精子超微结构的比较

利用透射电镜研究多线南蜥和印度蜓蜥附睾精子的超微结构。两种卵胎生石龙子的精子具有一些有鳞类精子的共同特征,即具有顶体囊、顶体下锥、单个核前穿孔器和核喙,无核内管,纤维鞘伸入中段,与双联微管3和8相邻的外周致密纤维具双份纤维结构。多线南蜥和印度蜓蜥精子超微结构的种间差异主要表现在:多线南蜥精子核前方的顶体下锥电子密度较小,顶体囊具单侧嵴,横切面上可见非连续的致密体环或11个线粒体;印度蜓蜥无单侧嵴,横切面上可见连续的致密体环或12个线粒体。迄今未发现石龙子科精子的独征,但该科不同类群的顶体囊、顶体下腔、核前方的顶体下锥电子致密程度、核肩、纵切面线粒体与致密体的排列方式、横切面致密体环形状和线粒体等精子超微结构特征有一定程度的差异。这些差异可为研究石龙子科系统发生提供辅助信息。

A comparison of the ultrastructure of spermatozoa of two species of skinks Mabuya multifasciata and Sphenomorphus indicus

We studied the ultrastructure of epididymal spermatozoa of two species of viviparous skinks,Mabuya multifasciata and Sphenomorphus indicus. Sperms of these two species do not differ in the following ultrastructure traits that are thought to be common in squamates: an acrosomal vesicle, a subacrosomal cone, a single prenuclear perforatorium, a nuclear rostrum, absence of an endonuclear canal, the fibrous sheath into the midpiece, and the peripheral dense fibers (presence as a double structure) adjacent to doublets 3 and 8. There are, however, salient differences between M.multifasciata and S.indicus in the ultrastructure of spermatozoa. The sperm of M.multifasciata is characterized by a more lucent epinuclear zone, a unilateral ridge in the acrosome, non-continuous ring structure formed by the dense body or 11 mitochondria in the transverse section. On the contrary, the sperm of S.indicus lacks a unilateral ridge in the acrosome, and it is characterized by continuous ring structure formed by the dense body or 12 mitochondria in the transverse section. Evidence for spermatozoal autapomorphies has not yet found in the family Sincidae, but sperms do differ, in various degrees, among different taxa of skinks in such ultrastructure traits as acrosome vesicle, subacrosomal space, transparency in epinuclear zone, nuclear shoulder, arrangement of mitochondria and dense bodies in the longitudinal section, ring structure formed by the dense body and mitochondria in the transverse section. These differences suggest that sperm morphology provides additional information which can be used to study phylogeny of Sincidae.