Gamasomorpha cf. vianai Birabén, 1954

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 : 9-10

Gamasomorpha cf. vianai Birabén, 1954

SPERM TRANSFER FORM ( fig. 9 ): Very large (.30 Mm), cone-shaped synspermia that presumably comprise four sperm, which are loosely arranged ( fig. 9A, B ). In the periphery of the sperm conjugate irregular tubelike membranes, originating from membrane invaginations, are visible ( fig. 9C ). The cytoplasm is heterogeneous, numerous electron-dense droplets and lamellae are visible ( fig. 9B, C ). The nuclei are elongated, cross sections reveal helical contortion, indicated by curls of the nuclei ( fig. 9B ). Numerous mitochondria are present. A thin, homogeneous secretion sheath (, 80 nm) surrounds the sperm conjugates ( fig. 9A, C ). The chromatin of mature spermatozoa is irregularly condensed ( fig. 9D ).

SPERMATOZOA ( figs. 9 ): Acrosomal complex: AV cylindrical; narrow subacrosomal space, ( fig. 9C ). AF originates from the subacrosomal space, extends into NC. Nucleus: prcN elongated ( fig. 9A, B ), with conspicuous chromatin-condensation pattern ( fig. 9A, D ). Implantation fossa very small and contains only centrioles. peN not identifiable. NC located in the periphery, empty for the most part. Axoneme: short, indicated by only few cross sections that are visible in the sperm conjugate ( fig. 9B ); 9+3 axonemal pattern ( fig. 9B ).

NOTES ON SPERMIOGENESIS ( fig. 10 ): The small developing acrosomal vacuole with a narrow subacrosomal space ( fig. 10A inset) separated from the nucleus by a distinct electron-dense plate ( fig. 10A ). At the posterior pole of the nucleus both centrioles migrate toward the latter, initiating the formation of a small implantation fossa ( fig. 10B ). The nucleus elongates markedly while the chromatin condenses irregularly, resembling an electron-dense thread in midspermatids ( fig. 10C ). Mature spermatozoa remain the irregularly condensed chromatincondensation pattern ( fig. 10D, E ). At the end of spermiogenesis four spermatids fuse ( fig. 10E ) to form a very large sperm conjugate. The manchette of microtubules disintegrates during further sperm conjugate differentiation.

Figures

Fig. 9. Characteristics of synspermia of Gamsomorpha cf vianai. A: Within the deferent ducts and the ejaculatory duct numerous very large sperm conjugates (.25 Mm) are visible. B: The nuclei are helically contorted as indicated by curls of the latter that are visible in cross sections. C: A thin secretion sheath surrounds sperm conjugates. The periphery of the syncytium is built by numerous constrictions of its membrane. D: The most obvious sperm characteristic is the peculiar chromatin-condensation pattern.

Fig. 10. Characteristics of spermiogenesis of Gamasomorpha cf vianai. A: The small AV is separated from the nucleus by a distinct electron-dense border; the narrow subacrosomal space contains the AF (inset). B: The chromatin starts condensation selectively in small spots within the nucleus. The very small IF contains only the two centrioles, the Ax, which has a typical 9+3 microtubular pattern (inset), originates from the distal centriole and extends into a flagellar tunnel. C: A small NC that contains the AF is located in the periphery of the nucleus. The nucleus of all stages of spermiogenesis is surrounded by a singlelayered manchette of microtubules. D: Late spermatids show the peculiar chromatin-condensation pattern, which resembles a furled sleeve in longitudinal sections. E: At the end of spermiogenesis, four spermatids entirely fuse to form large sperm conjugates. The NC is empty for the most part; the manchette of microtubules disintegrates during further sperm conjugate development.