Sperm ultrastructure in three different families of weakly electric fishes (Teleostei: Gymnotiformes)This study presents details of sperm ultrastructure for Gymnotus aff. carapo (Gymnotidae), Eigenmannia trilineata (Sternopygidae), and three Brachyhypopomus species (B. draco, B. bombilla, and B. gauderio - Hypopomidae) from southern Brazil. Differences were found among the representatives of the different families. For example, nuclear rotation was present in E. trilineata and in the Brachyhypopomus species, but absent in Gymnotus aff. carapo, and the presence of flagellar fins was only observed in E. trilineata. Some intraspecific variations could also be noticed among the Brachyhypopomus species analyzed. Most of the characters found in the spermatozoa of the species studied herein are shared with species of Gymnotiformes previously analyzed.
Gymnotidae; Hypopomidae; Spermatozoa; Sternopygidae
