Alberti Gerd, Ehrnsberger Rainer
Allgemeine und Systematische Zoologie, Zoologisches Institut und Museum, Ernst-Moritz-Arndt-Universität Greifswald, J.-S.-Bach-Str. 11/12, Greifswald, 17489, Germany.
Institut für Didaktik der Naturwissenschaften, Universität Vechta, Driverstr. 22, Vechta, 49377, Germany.
J Morphol. 2015 Jul;276(7):832-59. doi: 10.1002/jmor.20384. Epub 2015 Apr 4.
The male genital system of the actinotrichid mite Rhagidia halophila is described and compared with other mites and arachnids. The large testes are composed of germinal and glandular parts and produce numerous small sperm cells. The glandular parts are connected via a testicular bridge. Spermiogenesis occurs in cysts containing spermatids in equal stages of development. Cysts of spermatids are embedded in huge somatic cells. The nuclei of the spermatids loose their envelope. Mature sperm cells are simple exhibiting a ring-shaped chromatin body and lacking an acrosomal complex. They are most similar to the sperm cells of the related mite Linopodes motatorius. The spermatopositor contains the ejaculatory duct divided into a dorsal channel and a ventral channel that are connected via a narrow passage. At its distal end, the spermatopositor is divided into three eugenital lips. The function of the spermatopositor during deposition of the peculiar thread-like spermatophores is discussed. Details of the sensilla of the spermatopositor and the progenital lips are reported. The genital papillae located on the inner side of the progenital lips exhibit characteristics of cells performing transport of ions and/or water. The results confirm the overall similarity of actinotrichid genital systems, which is profoundly different from that of anactinotrichid mites. With reference to other Arachnida it is corroborated that testes and sperm structure of Actinotrichida are most similar to that of Solifugae. However, synapomorphies between sperm cells of Rhagidia and Solifugae that could suggest a closer relationship between these two taxa as was suggested in earlier studies were not recognizable. On the contrary, the sperm cells of Rh. halophila being devoid of an acrosomal complex appeared to be more apomorphic than those of many other actinotrichid mites as well as Solifugae.
描述了嗜盐裂须螨的雄性生殖系统，并将其与其他螨类和蛛形纲动物进行了比较。大型睾丸由生殖部分和腺体部分组成，产生大量小精子细胞。腺体部分通过睾丸桥相连。精子发生在含有处于相同发育阶段的精子细胞的囊中。精子细胞囊嵌入巨大的体细胞中。精子细胞的细胞核失去其包膜。成熟精子细胞结构简单，呈现环形染色质体且缺乏顶体复合体。它们与相关螨类动毛螨的精子细胞最为相似。输精器包含射精管，射精管分为背侧通道和腹侧通道，二者通过一条狭窄通道相连。在其远端，输精器分为三个生殖唇。讨论了输精器在特殊丝状精包沉积过程中的功能。报告了输精器和生殖唇的感觉器细节。位于生殖唇内侧的生殖乳头呈现出执行离子和/或水运输功能的细胞特征。结果证实了裂须螨生殖系统的总体相似性，这与无裂须螨的生殖系统有很大不同。参照其他蛛形纲动物，证实裂须螨目的睾丸和精子结构与避日蛛目最为相似。然而，如早期研究所暗示的，裂须螨和避日蛛精子细胞之间可能表明这两个类群关系更密切的共衍征并不明显。相反，嗜盐裂须螨的精子细胞缺乏顶体复合体，似乎比许多其他裂须螨类螨以及避日蛛的精子细胞更具衍生特征。
