Acta Parasitologica

, Volume 51, Issue 3, pp 200–208

Ultrastructure of spermiogenesis and mature spermatozoon of Skrjabinoporus merops (Cyclophyllidea, Metadilepididae)

  • Aneta Yoneva
  • Katia Georgieva
  • Yana Mizinska
  • Boyko B. Georgiev
  • Stoyanka R. Stoitsova
Article

DOI: 10.2478/s11686-006-0031-7

Cite this article as:
Yoneva, A., Georgieva, K., Mizinska, Y. et al. Acta Parasit. (2006) 51: 200. doi:10.2478/s11686-006-0031-7
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Abstract

The ultrastructure of the mature spermatozoon and the spermiogenesis of a cestode belonging to the family Metadilepididae is described for the first time. The mature spermatozoon of Skrjabinoporus merops is characterized by twisted peripheral microtubules, the presence of a single crested body, periaxonemal sheath and electron-dense rods, and the absence of intracytoplasmic walls and inclusions (glycogen or proteinaceous granules); no peripheral microtubules where nucleus contacts the external plasma membrane. Four morphologically distinct regions of the mature spermatozoon are differentiated. The proximal part (Region I) contains a single crested body, periaxonemal sheath is absent in some (proximal) sections and is present in others situated closer to the nucleus. The central Region II is nucleated, and is followed by Region III that contains a periaxonemal sheath. The distal pole, Region IV, is characterized by disintegration of the axoneme. Spermiogenesis follows the type III pattern (Bâ and Marchand 1995) although in S. merops a slight flagellar rotation is observed. The differentiation zone is characterized by the absence of striated roots and intercentriolar body; two centrioles are present, one of which gives rise to a free flagellum. The latter rotates and undergoes proximodistal fusion with the cytoplasmic protrusion of the differentiation zone. Spermiological characters of S. merops are similar to those of the families Taeniidae and Catenotaeniidae. The mature spermatozoon differs from those of the Dilepididae (where the metadilepidid species have previously been classified) by the lack of glycogen.

Key words

Cyclophyllidea Metadilepididae Skrjabinoporus merops spermatozoon spermiogenesis ultrastructure 

Copyright information

© W. Stefański Institute of Parasitology, PAS 2006

Authors and Affiliations

  • Aneta Yoneva
    • 1
  • Katia Georgieva
    • 1
  • Yana Mizinska
    • 1
  • Boyko B. Georgiev
    • 2
    • 3
  • Stoyanka R. Stoitsova
    • 4
  1. 1.Institute of Experimental Pathology and ParasitologyBulgarian Academy of SciencesSofiaBulgaria
  2. 2.Central Laboratory of General EcologyBulgarian Academy of SciencesSofiaBulgaria
  3. 3.Departament of ZoologyNatural History MuseumLondonUK
  4. 4.Institute of MicrobiologyBulgarian Academy of SciencesSofiaBulgaria