Evolutionary Morphology Of The Primary Male Reproductive System And Spermatozoa Of Goblin Spiders (Oonopidae; Araneae) Author Lipke, Elisabeth Author Michalik, Peter text Bulletin of the American Museum of Natural History 2015 2015-09-24 2015 396 1 72 http://www.bioone.org/doi/10.1206/906.1 journal article 7643 10.1206/906.1 15ad630f-eff2-451d-a5f8-22731ff53851 0003-0090 4612269 Paradysderina fusiscuta Platnick and Dupérre´, 2011 SPERM TRANSFER FORM ( fig. 30 ): Large (,12 Mm), mainly oval synspermia ( fig. 30A, B ) comprising four sperm. Numerous membranes are located in the periphery ( fig. 30C ), as well as among all sperm components ( fig. 30E ). Thus, although fused, each sperm remains surrounded by its own membrane ( fig. 30D ). The deep implantation fossa is completely filled with mitochondria ( fig. 30 E ). In addition, there are numerous mitochondria located in the peripheral cytoplasm ( fig. 30F ). A thin, homogeneous secretion sheath (, 50 nm ) surrounds the sperm transfer forms ( fig. 30F ). SPERMATOZOA ( fig. 30 ): Acrosomal complex: AV small, cylindrical with narrow subacrosomal space. AF originates from the subacrosomal space and extends into the nuclear canal, clearly ends after the axonemal base ( fig. 30F ). Nucleus: prcN extremely elongated, providing a deep implantation fossa that is completely filled with mitochondria ( fig. 30 D–F). peN long and oval shaped ( fig. 30D ), contains parts of the implantation fossa. NC located in the periphery. Axoneme: very long, always in close association with the nucleus ( fig. 30D ); 9+3 microtubular pattern ( fig. 30D, F ). NOTES ON SPERMIOGENESIS ( fig. 31 ): Within the testis all stages of spermiogenesis are present. Spermatids of the same developmental stage are arranged in cysts. Early spermatids are characterized by a large, mainly spherical nucleus that is surrounded by a manchette of microtubules. The acrosomal complex, which is composed of a small, cylindrical AV and the AF, is formed at the anterior pole of the nucleus ( fig. 31A ). The AV is attached to the cell membrane ( fig. 31 A, B ); proximally it is surrounded by some electron-dense material ( fig. 31B ). The wide implantation fossa at the posterior pole of the nucleus is filled with numerous, small mitochondria ( fig. 31C, D ). It extends toward the prcN, as well as into the peN ( fig. 31D ). Further differentiation of the spermatid includes chromatin condensation that consequently appears fibrillar ( fig. 31E ) and an enormous elongation of the nucleus. The Ax curls around the latter ( fig. 31E, F ). The chromatin of late spermatids is highly condensed ( fig. 31G ). At the end of spermiogenesis, four slender spermatids arrange closely attached to each other. The main cell components coil within the cell membrane, while the cellular bridges widen and secondarily surround the main sperm cell components. The fused sperm are the subject to several differentiations including partial restriction of common cytoplasm and further coiling processes, before large sperm conjugates are released into the lumen of the testis ( fig. 31H ).