Silhouettella loricatula ( Roewer, 1942 )
publication ID |
https://doi.org/ 10.1206/906.1 |
DOI |
https://doi.org/10.5281/zenodo.4628199 |
persistent identifier |
https://treatment.plazi.org/id/03E487E0-3028-2150-2ED9-A17F661C7D0A |
treatment provided by |
Felipe |
scientific name |
Silhouettella loricatula ( Roewer, 1942 ) |
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Silhouettella loricatula ( Roewer, 1942) View in CoL
SPERM TRANSFER FORM ( fig. 37 View Fig ): Large, cone-shaped synspermia comprising four sperm. The cytoplasm of the syncytium is heterogeneous and numerous electron-dense plates and droplets, as well as electron-lucent gaps occur ( fig. 37A, B View Fig ). The most obvious characteristic is the distinct, irregular chromatin-condensation pattern ( fig. 37B, C View Fig ). Numerous platelike membrane stacks are visible in the periphery of the sperm conjugate ( fig. 37D View Fig ). A thin homogeneous secretion sheath (, 100 nm) surrounds each sperm conjugate ( fig. 37A, B, D View Fig ).
SPERMATOZOA ( fig. 37 View Fig ): Acrosomal complex: AV cylindrical. AF originates from the subacrosomal space and extends into the nuclear canal. Nucleus: prcN elongated, characterized by a conspicuous irregular chromatin-condensation pattern ( fig. 37 View Fig A– C) and a very small implantation fossa that contains only the two centrioles ( fig. 37B View Fig ). peN not visible in mature sperm; NC located in the periphery ( fig. 37C View Fig ), but empty for the most part ( fig. 37C View Fig ). Axoneme: 9+3 microtubular pattern.
NOTES ON SPERMIOGENESIS ( fig. 38 View Fig ): The anterior portion of the prcN is deeply indented and surrounds the AV ( fig. 38A, B View Fig ) in addition to a little electron-dense material ( fig. 38B View Fig ). Besides the AF the subacrosomal space contains some granular material ( fig. 38B View Fig ). The chromatin starts condensation around the nuclear canal ( fig. 38C, D View Fig ) before the characteristic chromatin-condensation pattern is formed ( fig. 38 F View Fig ). While the nucleus elongates and the chromatin starts to condense, a small dropletlike elongation of the nucleus is formed ( fig. 38E View Fig ). This peN probably disintegrates in further development. The implantation fossa is very small and contains only the two centrioles ( fig. 38F View Fig ). Neither the centrioles nor the axoneme ( fig. 38F View Fig inset) are surrounded by electron-dense material.
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