Comparative Spermatology of Protura and Its Significance on Proturan Systematics

A comparative study on the ultrastructure of the spermatozoa of 20 species of Protura belonging to 16 genera and 8 families was conducted. The most remarkable characteristics are the unexpected diversity of the spermatozoa, both in shape and fine structure. In general they can be grouped into two main categories: long flagellate spermatozoa and short aflagellate ones. Accordingly two sperm evolutionary lines of the spermatozoa were obtained: one trends towards the complicated acrosome structure and the increased number of axonemal doublets, and the other line is to shorten cell form and simplify sperm structure. The results indicate that the spermatozoa of Hesperentomon may be the primitive type, and the spermatozoa of Eosentomids probably represent the most evolved type. A sperm evolutionary tree was drawn according to the apomorphies of proturan spermatozoa. The phylogenetic position of Protura was also discussed.     

原尾虫比较精子学的研究及其在系统分类学上的重要意义

通过对8科、16属和20种原尾虫的精子,进行了超微结构观察和比较,发现其精子极富多样性,主要可分成具鞭毛的长形精子和无鞭毛的短形精子两大类,精子的演化趋势一类是顶体构造渐趋复杂,轴丝双微管的数目渐趋增多;另一类是精子的形状逐渐短缩,结构逐渐简化,经过比较和分析,确认夕蚖的精子是已知原尾虫各属中最为原始的,古蚖等属的精子是最为特化的类型,除根据精子的衍征制成系统演化树外,还就精子的形态讨论了原尾虫的系统分类地位。