Spermiogenesis and sperm ultrastructure of Asetocalamyzas laonicola Tzetlin, 1985 (Polychaeta), an ectoparasite of the large spionid Scolelepis cf. matsugae Sikorsfi, 1994, from the White Sea

Authors

  • Elena V. Vortsepneva Department of Invertebrate Zoology, Moscow State University, Moscow
  • Anna E. Zhadan Ecological Center, Moscow State University, Moscow
  • Alexander B. Tzetlin Department of Invertebrate Zoology, Moscow State University, Moscow

DOI:

https://doi.org/10.3989/scimar.2006.70s3343

Keywords:

spermiogenesis, sperm ultrastructure, Asetocalamyzas laonicola, Scolelepis cf. matsugae

Abstract


The sperm ultrastructure and spermatogenesis of the ectoparasitic polychaete Asetocalamyzas laonicola Tzetlin, 1985 (Calamyzidae) is investigated. The male cells are located freely in the coelom. The spermatocytes are large cells of irregular shape; their nuclei have condensed chromatin in the periphery. Spermatocyte cytoplasm is granular and electron-dense with several spherical mitochondria. During early developmental stages spermatids are aggregated into a rosette (four cells). The early spermatids have a tiny acrosomal vesicle at one side of the cell, a few round mitochondria at another, and electron dense nuclei. The late spermatids have elongated mitochondria, a well-developed acrosome and a flagellum. The mature sperm are threadlike with a round acrosomal vesicle, an electron-dense structure. The elongated nuclei have anterior and posterior depressions. The supporting root zone of the acrosome is located behind the acrosomal vesicle in the anterior invagination of the nuclei. Six elongated mitochondria surround the flagellum and form the midpiece of the sperm. A single centriole lies in the posterior depression of the nucleus. The middle part of the flagellum possesses a normal (9+2x2) pattern. Probably, the terminal part of flagellum is modified. The sperm structure suggests internal fertilization or another type of specialized sperm transfer in A. laonicola.

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Published

2006-12-30

How to Cite

1.
Vortsepneva EV, Zhadan AE, Tzetlin AB. Spermiogenesis and sperm ultrastructure of Asetocalamyzas laonicola Tzetlin, 1985 (Polychaeta), an ectoparasite of the large spionid Scolelepis cf. matsugae Sikorsfi, 1994, from the White Sea. Sci. mar. [Internet]. 2006Dec.30 [cited 2024Mar.28];70(S3):343-50. Available from: https://scientiamarina.revistas.csic.es/index.php/scientiamarina/article/view/140

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