Bryconacidnus ellisi (Pearson, 1924)

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 : 381

Bryconacidnus ellisi ( Fig. 5 A-E)

In the spermatozoon of Bryconacidnus ellisi , the ovoid nucleus measures 1.7 µ m in the longitudinal axis and 1.4 µ m in the transverse axis. The surrounding strip of cytoplasm has no organelles ( Fig. 5A ). Nuclear rotation toward the flagellar axis was about 80 degrees ( Fig. 5A ). The midpiece has a conical shape, measures approximately 0.5 µ m in length and contains some elongate mitochondria. The endomembrane system is composed by small vesicles with a lacy aspect and connected to the plasma membrane ( Fig. 5 B-E).

Figures

Fig. 5. Spermatozoa of Bryconacidnus ellisi. A-B: 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). The lacy-like endomembrane system (v) is distributed throughout the midpiece. C-E: Cross sections through the middle of the nucleus and at different levels of the strongly asymmetric midpiece, exposing the lateral position of the cytoplasmic canal (*) and flagellum (f), the distribution of the few long mitochondria (m) accumulated in larger portion of the midpiece.