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 Neoxyphinus termitophilus ( Bristowe, 1938 ) SPERM TRANSFER FORM ( figs. 18 , 19 ): Large (,25 Mm), oval-shaped synspermia (within the ejaculatory duct) comprising four sperm ( fig. 18 ). Synspermia, located in the deferent ducts, are bottle shaped ( fig. 18 ). The bottleneck contains the acrosomal vacuoles, the short and helically contorted precentriolar parts of the nucleus and the base of the axonemes, as well as postcentriolar elongations of the nucleus, whereas the voluminous bulge is filled with the main parts of axonemes and postcentriolar elongations of nucleus that coil around each other. Numerous mitochondria are located in the periphery of the sperm conjugate ( fig. 19A, B ). A very thin and loosely appearing secretion sheath (, 30 nm ), which is produced Fig. 23. Characteristics of synspermia of Oonops sp. (Ibiza). A : Sperm conjugates, which are composed of two sperm, arrange in cluster. B : Synspermia are not provided with a secretion sheath, but show a distinct electron-dense vesicular area. C : The condensed chromatin appears fibrillar, distinct electronlucent stalks appear, and the cytoplasm appears granular in sperm conjugates. D : The NC is located on a distinct projection, running in the periphery of the nucleus; note mitochondria within the cytoplasm. E : The base of the axoneme, with a typical 9+3 microtubular pattern (inset), is associated with a little electron-dense material. F : Note a small amount of glycogen is present in the IF, as well as within the cytoplasm of the sperm conjugate. A thin ribbon originating from the vesicular area is located in the periphery of the sperm conjugate underneath the membrane of syncytium. Fig. 24. Characteristics of spermiogenesis of Oonops sp. (Ibiza). A : The small developing AV is attached to the cell membrane anteriorly (magnification in inset); the nucleus is surrounded by a manchette of microtubules. B : The chromatin condenses irregularly and appears fibrillar in midspermatids. C : The elongated AV is surrounded by electron-dense material (arrow) at the anterior pole of the nucleus. D : The AF extends into the NC that is located on a distinct projection in the periphery of the nucleus. E : At the end of spermiogenesis, the main cell components coil within the cell membrane, while the spermatids remain connected with each other via cellular bridges. F : Finally, two spermatids fuse, forming a mainly spherical sperm conjugate. in the ejaculatory duct, surrounds the sperm conjugates ( fig. 19 A–C). SPERMATOZOA ( figs. 18 , 19 ): Acrosomal complex: AV short (,1.2 Mm) and cylindrical Fig. 25. Characteristics of the sperm transfer form of Opopaea apicalis . A : The STF is only composed of a condensed chromatin thread that is embedded in electron-dense cytoplasm and surrounded by a thin secretion sheath. B : Within the periphery of the STF distinct electron-lucent portions are visible. C : The chromatin thread is highly coiled, as is most obvious in late stages of spermiogenesis. D : The manchette of microtubules surrounds the chromatin thread. E : During the sperm development, the nucleus becomes extremely elongated, as indicated by numerous cross sections that are visible within one cell. Further cell components, such as an acrosomal complex, or an Ax are not developed. ( fig. 18 ). AF originates from the subacrosomal space and extends into the nuclear canal but ends clearly ends before the axonemal base. Nucleus: prcN short (,10.1 Mm), helically contorted with medium-sized implantation fossa that is filled with numerous mitochondria ( fig. 19A ), several spherical secretions, proximal and distal centriole, as well as the base of the Ax. peN extremely elongated (,171.8 Mm), oval in cross sections with distinct projection ( fig. 19A, E ). NC located within a distinct projection, twists around the peN ( figs. 18 , 19A, E ) but is empty for the most part ( fig. 19D ). Axoneme: extremely long (,291.5 Mm); centrioles arranged in tandem position; 9+3 axonemal pattern ( fig. 19B, E ). Fig. 26. Surface reconstruction of parts of the highly convoluted deferent ducts and sperm transfer forms of Orchestina sp. 1. (Chile), as based on serial light-microscopy images, illustrating the shape and arrangement of synspermia within the lumen of the deferent duct and the two fused sperm within one sperm conjugate. The axoneme is hypothetically reconstructed based on the presence of dense microtubular network within the cytoplasm of the sperm conjugate. NOTES ON SPERMIOGENESIS: Within the testis all stages of spermiogenesis are present, developing spermatids are arranges in cysts. Early spermatids are characterized by a large, oval nucleus that is surrounded by a manchette of microtubules. Mid spermatids are characterized by a small, cylindrical AV ( fig. 20A, B ) that is partly sunken into the anterior pole of the nucleus and accompanied by a small amount of electron-dense material ( fig. 20B ). Further development includes condensation of chromatin that appears fibrillar in mid spermatids ( fig. 20C, D ). Mitochondria are always present within the implantation fossa ( fig. 20D , F–H). Mid- and late spermatids show a characteristic chromatin-condensation pattern in which a small portion remains homogeneously electron lucent ( fig. 20E, E inset). The axoneme is twisted around the postcentriolar elongation, thus both cell components seem to interact ( fig. 20F ). In late spermatids, both centrioles are arranged in tandem position ( fig. 20G ). The implantation fossa is filled with numerous mitochondria ( figs. 20 F–H). The two centrioles and the base of the Ax are surrounded by electron-dense secretion droplets and electron-dense secretion plates ( fig. 20H ). At the end of spermiogenesis four spermatids fuse and form large and voluminous synspermia. During early stages of this sperm conjugation, four mainly individualized spermatids that remained connected to each other via cellular bridges arrange in close association. While the Ax’s, as well as peN’s coil, and form the massive bulge of early bottle-shaped synspermia, the cellular bridges widen posteriorly resulting in a large amount of common cytoplasm. Finally, the common cytoplasm, which contains numerous mitochondria, encases the spermatids secondarily during further differentiation of the sperm conjugate.