Paradysderina fusiscuta Platnick

Lipke, Elisabeth & Michalik, Peter, 2015, Evolutionary Morphology Of The Primary Male Reproductive System And Spermatozoa Of Goblin Spiders (Oonopidae; Araneae), Bulletin of the American Museum of Natural History 2015 (396), pp. 1-72 : 48

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 ).

Figures

Fig. 30. Characteristics of synspermia of Paradysderina fusiscuta. A: The lumen of the deferent ducts is filled with large sperm conjugates. B: Sperm conjugates are composed of four sperm, which are randomly arranged and curled around each other. C: All sperm conjugates are surrounded by a very thin secretion sheath. Numerous membranes, as well as small folds are visible in the periphery. D: Sperm are not entirely fused, thus the main sperm cell components remain surrounded by their own membrane. E: The deep implantation fossa is filled with numerous mitochondria that are arranged in a row. F: Additional mitochondria are present in the periphery of the sperm conjugate.

Fig. 31. Characteristics of spermiogenesis of Paradyderina fusiscuta. A: A small, fingerlike AV is formed at the anterior pole of the nucleus. B: The posterior portion of AV is accompanied by electrondense material. C: At the posterior pole of nucleus a wide IF is formed. D: Numerous mitochondria are located in the IF. E: The chromatin appears fibrillar in mid spermatids. F: At the end of spermiogenesis four spermatids, which remained connected to each other via cellular bridges, arrange closely attached to each other and partly fuse. G: Finally, they form a large sperm conjugate, in which the main cell components of all spermatids coil. H: Additional mitochondria are located in the periphery of the sperm conjugate.