Piabina argentea (Fig. 14 A-E) In the spermatozoon of Piabina argentea the ovoid nucleus measures 1.52 µ m in the longitudinal axis and 1.2 µ m in the transverse axis. The surrounding strip of cytoplasm has no organelles (Fig. 14A). Nuclear rotation toward the flagellar axis was about 85 degrees (Fig. 14A). The midpiece has a conical shape, measures about 0.6 µ m in length and contains some elongate mitochondria (Fig. 14A,C-E). Information on the endomembrane system is not available, since the specimens of P. argentea have been obtained from ichthyological collections and the gonads were not appropriately preserved for ultrastructural analysis.

Published as part of 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), pp. 377-392 in Neotropical Ichthyology 9 (2) on page 383, DOI: 10.1590/S1679-62252011005000014, http://zenodo.org/record/5422771