Tinadysderina otonga Platnick, Berniker and, 2013

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 : 51

Tinadysderina otonga Platnick, Berniker and

Bonaldo, 2013

SPERM TRANSFER FORM ( fig. 40 ): Large (,12 Mm), disclike synspermia ( fig. 40A, B ) comprising four spermatozoa. Sperm conjugates are flattened, disclike and resemble a dumbbell in cross sections ( fig. 40A, B ). All sperm conjugates show numerous bacteria occupying the nuclei ( fig. 40 , D, E). Infected sperm are already visible in the testis, where the spermatid development is likely influenced by means of, e.g., a partially deficient chromatin condensation ( fig. 40E inset). A thin, homogeneous secretion sheath (, 80 nm) surrounds the sperm conjugates ( fig. 40 F ).

SPERMATOZOA ( fig. 40 ): Acrosomal complex: AV conical, thus widened posteriorly ( fig. 40C ), possessing a narrow subacrosomal space ( fig. 40C ). AF originates from the subacrosomal space and extends into the nuclear canal, but clearly ends before the base of the Ax. Nucleus: prcN elongated, tubelike with deep implantation fossa that contains numerous mitochondria ( fig. 40E ), as well as electron-dense secretions. peN long, oval shaped. NC located in the periphery, empty for the most part ( fig. 40D ). Axoneme: 9+3 microtubular pattern.

NOTES ON SPERMIOGENESIS ( fig. 41 ): Within the testis, all stages of spermiogenesis are visible. Spermatids develop in large cysts. Early spermatids are characterized by, e.g., a large, oval nucleus, and a developing acrosomal complex ( fig. 41A, B ). Besides the AF the subacrosomal space possesses little electron-dense material ( fig. 41B ). The nucleus of early spermatids is slightly indented at its anterior pole ( fig. 41B ). At its posterior pole, a large implantation fossa, containing numerous small mitochondria, is formed ( fig. 41C ). Further spermatid development includes chromatin condensation, which appears fibrillar in mid spermatids ( fig. 41C ). As a consequence, the nucleus elongates extremely and involves certain shape changes, finally resulting in a tubelike appearance. The nucleus is always surrounded by a manchette of microtubules ( fig. 41D ), which disintegrates after sperm conjugation. Additional microtubules located near other cell components are visible in all developmental stages ( fig. 41E ). The implantation fossa contains little electron-dense secretions, in addition to numerous mitochondria. The two centrioles are arranged in tandem position in late spermatids (41F). At the end of spermiogenesis four spermatids fuse ( fig. 41G ). These large, early sperm conjugates are characterized by a large, electron-lucent cytoplasm in the center ( fig. 41G ), and numerous membranes, as well as Golgi derivatives ( fig. 41G ). The cell membrane of the syncytium is irregularly folded in the periphery ( fig. 41G ). Further development includes condensation of cytoplasm.

Figures

Fig. 40. Characteristics of synspermia of Tinadysderina otonga. A: Numerous synspermia are located in the lumen of the deferent ducts, additional secretions are not detectable. B: Sperm conjugates are disclike, thus they resemble a dumbbell in cross sections. C: The subacrosomal space is widened toward the anterior pole of nucleus, resulting in a conical shape of the AV. D: Numerous endosymbionts occur within the nucleus of the sperm. E: The nucleus appears torn in some sperm, which is probably related to the endosymbiont infection and might affect the chromatin condensation (inset). F: The irregularly folded membrane of syncytium is surrounded by a thin secretion sheath.

Fig. 41. Characteristics of spermiogenesis of Tinadysderina otonga. A: The implantation fossa of early spermatids is already filled with a large amount of mitochondria. B: The subacrosomal space is enlarged toward the anterior pole of nucleus. C: The chromatin appears fibrillar in mid spermatids. D: During further development, the chromatin condenses irregularly as indicated by the manchette of microtubules, which illustrates the actual dimensions of the nucleus. E: Little electron-dense material surrounds the microtubules of the axoneme. F: In addition to mitochondria, small electron-dense secretions are located in the IF. G: At the end of spermiogenesis four spermatids fuse to form synspermia.