Paradysderina yanayacu 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 : 49

Paradysderina yanayacu Platnick and Dupérre´, 2011

SPERM TRANSFER FORM ( figs. 32 , 33 ): Large (,12 Mm), oval-shaped synspermia ( fig. 33A, B ) comprising four sperm ( fig. 32 ). Numerous membrane stacks are visible ( fig. 33 C, D ). Sperm are coiled and curled around each other ( figs. 32 , 33E, F ). A homogeneous secretion sheath (, 250 nm) surrounds the sperm transfer forms ( fig. 33 A–C).

Spermatozoa ( figs. 32 , 33 ): Acrosomal complex: AV small (,1.5 Mm), cylindrical ( fig. 32 ), with narrow subacrosomal space. AF originates from the narrow subacrosomal space and extends into the nuclear canal but clearly ends before the axonemal base. Nucleus: prcN elongated (,22.9 Mm) and helically contorted ( fig. 33E, F ). Surface reconstructions reveal a tubelike shape ( fig. 32 ). peN long (,61.9 Mm) and mainly oval in cross sections ( fig. 33B, C ). NC located in the periphery ( fig. 33C ) but empty for the most part ( fig. 33C ). Axoneme: long (,160.3 Mm). 9+3 microtubular pattern ( fig. 33 C–F). Little centriolar adjunct surrounds both centrioles, as well as the base of the Ax ( fig. 33F ). Moreover, the peripheral microtubules of the central portion of Ax are surrounded by electron-dense material ( fig. 33D ).

NOTES ON SPERMIOGENESIS ( fig. 34 ): Within the testis all stages of spermiogenesis are visible. Developing spermatids are arranged in cysts. Early spermatids are characterized by, e.g., a large, mainly spherical nucleus and a developing acrosomal complex. While the chromatin starts to condense it appears fibrillar ( fig. 34 A–C). The proximal portion of the small, cylindrical AV is enclosed by a little electron-dense material ( fig. 34A, B ). The nucleus is surrounded by a manchette of microtubules ( fig. 34C, F ). The deep and wide implantation fossa is filled with numerous mitochondria ( fig. 34C, D ). While the nucleus elongates the chromatin further condenses ( fig. 34D ). Dense chromatin of the precentriolar part of nucleus appears helically contorted around the implantation fossa ( fig. 34D ). Little electron-dense material is attached to the peripheral microtubules of the central Ax ( fig. 34E ). At the end of spermiogenesis four spermatids group closely attached and initiate curling around each other ( fig. 34F, G ). This process is certainly supported by microtubules that originate from the disintegrating manchette of microtubules and show a distinct arrangement ( fig. 34F ). The cytoplasm condenses and enlarged, widened cell membranes fold between the sperm, resulting in numerous membrane stacks and one prominent membrane whorl in the center of the sperm conjugate ( fig. 34G ).

Figures

Fig. 32. Surface reconstruction of synspermia of Paradysderina yanayacu, illustrating the shape and arrangement of all four fused sperm, as well as the arrangement of an individual sperm. Note the very long peN and Ax, which coil around each other within the membrane of syncytium.

Fig. 33. Characteristics of synspermia of Paradysderina yanayacu. A: Within the lumen of the deferent ducts, numerous large, oval-shaped sperm conjugates and two types of secretion are visible. B: Cross sections through an entire sperm conjugate showing the arrangement of sperm cell components of all four sperm, which are beginning to coil around each other. C: Synspermia are surrounded by a thin secretion sheath. D: Numerous, densely packed membranes are visible. E: The four spermatids coil around each other, thus the prcN appears helically contorted. F: A small amount of electron-dense material surrounds the peripheral microtubules at the base of the axoneme.

Fig. 34. Characteristics of spermiogenesis of Paradysderina yanayacu. A: A small AV that is attached to the cell membrane is formed at the anterior pole of nucleus. B: Little electron-dense material is associated with the posterior portion of the AV. C: The large IF contains numerous mitochondria. D: During the development of the spermatids the prcN extremely elongates and screws. E: Little electrondense material is associated with the peripheral microtubules in the axoneme. F: At the end of spermiogenesis four spermatids arrange closely attached to each other and finally form a large synspermium. G: Large membrane whirls are visible within the sperm conjugate.