Spermatogenesis of five rhabditid nematodes was studied using transmission electron microscopy and is described herein. Structure and development of nematode sperm in all available representatives of the extensive order Rhabditida have been analysed and the main characteristics of each infraorder are discussed. The ancestral sperm of the order Rhabditida was reconstructed using maximum likelihood and Bayesian methods based on 44 ultrastructural sperm characters. The hypothetical ancestral spermatogenesis of the order Rhabditida agrees with the previously suggested “rhabditid” pattern and appears to be conserved throughout the order Rhabditida. Despite the enormous variation of rhabditid nematodes, few groups deviate from the ancestral pattern. This conserved pattern can be informative within the phylum Nematoda at order level, but poses limitations when used in taxonomic and phylogenetic analysis within Rhabditida.

中文翻译：

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杆状线虫（Nematoda：Rhabditida）精子的结构、发育和进化模式

使用透射电子显微镜研究了五种杆状线虫的精子发生并在本文中进行了描述。已经分析了粗略目 Rhabditida 的所有可用代表中线虫精子的结构和发育，并讨论了每个亚目的主要特征。基于44个超微结构精子特征，使用最大似然法和贝叶斯方法重建了Rhabditida目祖先精子。假设的横纹肌目祖先精子发生与先前提出的“横纹肌群”模式一致，并且似乎在整个横纹肌目中都是保守的。尽管杆状线虫种类繁多，但很少有种群偏离祖先模式。这种保守的模式可以在目级别的线虫门内提供信息，