Escaphiella ramirezi 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 : 7-8

Escaphiella ramirezi Platnick and Dupérre´, 2009

SPERM TRANSFER FORM ( figs. 6 , 7 ): Very large, elongated synspermia (,70 Mm) that

comprise four spermatozoa ( fig. 7A, B ). Overall shape of this sperm conjugate bonelike ( fig. 6 ). A slender vesicular area surrounds all sperm-cell components ( fig. 7B, D, E ). The acrosomal vacuoles, which represent the anterior pole of sperm are located in the middle of the sperm conjugate ( fig. 6 , arrow), Two sperm arranged opposed to each other (two sperm coil clockwise, the remaining two counter clockwise). Cytoplasm of the sperm conjugate electron lucent. Numerous, circular Golgi derivatives are present, mainly located in the periphery of the sperm conjugate ( fig. 7 A–C) and sometimes associated with the membrane of the syncytium ( fig. 7C ). Synspermia surrounded by a thin (, 50 nm) secretion sheath ( fig. 8B, C ) that is produced in the deferent ducts.

SPERMATOZOA ( fig. 7 ): Acrosomal complex: AV very short (,1.9 Mm), cylindrical, narrow subacrosomal space ( fig. 8D ). AF originates from the subacrosomal space of the acrosomal vacuole and extends into the nuclear canal; ends in the region of the axonemal base ( fig. 7E ); extremely elongated (,125.2 Mm) and for most part remarkably large, resembling the most prominent cell component ( fig. 7B ). Nucleus: prcN extremely elongated (,126 Mm) ( fig. 6 ). Most pro- minent part of the prcN is the nuclear canal that contains the massive acrosomal filament (see above, figs. 6 , 7 B–E). Condensed chromatin is restricted to a small portion around the latter ( fig. 7 B–E). Implantation fossa extremely small, containing only the centrioles ( fig. 7E ). peN very short (,1.3 Mm) and thin, flag shaped ( figs. 6 , 7E ). Axoneme: short (,58.4 Mm), 9+3 microtubular pattern ( fig. 7B, D ); centrioles arranged rectangularly, proximal centriole very short.

NOTES ON SPERMIOGENESIS ( fig. 8 ): Cysts of developing sperm (mainly early and midspermatids) present within the testis. Early spermatids characterized by a small vesiclelike AV that is attached to the cell membrane ( fig. 8A ). Originating from the subacrosomal space, AF comprises only a few filaments in the AV as indicated by cross sections ( fig. 8 A ). In contrast, it expands to a massive rod composed of numerous filaments ( fig. 8 B–D) within NC. Nucleus is surrounded by a manchette of microtubules and chromatin appears fibrillar in early and midspermatids ( fig. 8B, C ). While nucleus elongates, condensed chromatin constricted to a small portion ( fig. 8D ). Axoneme originates from the distal centriole ( fig. 8E ). Occasionally, small electron-dense spots are present in the periphery, likely inside NC, associated with AF. At the end of spermiogenesis, several spermatids start to fuse, resulting in voluminous sperm conjugates that remain connected to each other via cellular bridges ( fig. 8F ). A loose, electron-dense network of fused vesicles, representing an early stage vesicular area, surrounds all main sperm cell components ( fig. 8F inset).

Figures

Fig. 6. Surface reconstruction of sperm transfer form of Escaphiella ramirezi illustrating the shape and arrangement of all four fused sperm cells, as well as the arrangement of an individual sperm and the acrosomal filament of an individual sperm. All AVs are located in the centre of the sperm conjugate (arrow), as indicated for one AV. Two sperm coil clockwise, while the remaining two coil counterclockwise. Note the extremely thick AF and the very thin, flag shaped peN (asterisk).

Fig. 7. Characteristics of synspermia of Escaphiella ramirezi. A: Due to the peculiar shape of the bonelike sperm conjugate cross sections are either oval shaped or spherical. B: A small VA surrounds the sperm cell components secondarily. C: Numerous Golgi derivatives, sometimes attached to the membrane of the syncytium are visible within the sperm conjugate; a thin secretion sheath surround the entire synspermium. D: The AVs have a narrow subacrosomal space from which the AF originates. E: The AF enlarges and extends into the NC but clearly ends before the axonemal base, the postcentriolar elongation is very short and flag shaped.

Fig. 8. Characteristics of spermiogenesis of Escaphiella ramirezi. A: The small AV of early spermatids is attached to the cell membrane and separated from the nucleus by distinct electron-dense plates (arrow). B: The AF is thin near its origin within the subacrosomal space but enormously expands while extending into the nucleus. C: Numerous filaments that build the AF are visible in cross sections. D: A manchette of microtublues surrounds the nucleus. The small implantation fossa contains only the centrioles. E: At the end of spermiogenesis the main cell components coil within the cell membrane and two spermatids fuse. F: These large, early sperm conjugates are still connected to each other via cellular bridges (asterisks); a loose, electron-dense network arranges around the sperm cell components, forming a small vesicular area (inset).