Knodus meridae, Eigenmann, 1911

Baicere-Silva, Clarianna Martins, Ferreira, Katiane M., Malabarba, Luiz R., Benine, Ricardo C. & Quagio-Grassiotto, Irani, 2011, Spermatic characteristics and sperm evolution on the subfamily Stevardiinae (Ostariophysi: Characiformes: Characidae), Neotropical Ichthyology 9 (2), pp. 377-392 : 382

Knodus meridae ( Fig. 11 A-E)

In the spermatozoon of Knodus meridae , the ovoid nucleus measures 1.3  m in the longitudinal axis and 1.1  m

in the transverse axis. The surrounding strip of cytoplasm has no organelles ( Fig. 11 A-D). Nuclear rotation toward the flagellar axis was about 75 degrees ( Fig. 11A ). The midpiece has a rhomboid shape, measures about 0.9  m in length and contains some elongated mitochondria and vesicles ( Fig. 11 A-E). Information on the organization of the endomembrane system is not available, since the specimens of K. meridae have been obtained from ichthyological collections and the gonads were not appropriately preserved for ultrastructural analysis.

Figures

Fig. 11. Spermatozoa of Knodus meridae. A-D: Longitudinal sections of spermatozoa. Note the lateral position of the nucleus (n) in relation to the flagellar axis and to proximal (p) and distal (d) centrioles, the eccentric position of the double nuclear fossa (double arrow), the midpiece and the cytoplasmic canal (*) containing the initial segment of the flagellum (f). E: Elongate mitochondria (m) and vesicles (v) are located in larger portion of the midpiece.