Morphological study of the spermatogenesis in the teleost Piaractus mesopotamicus

ABSTRACT: The spermatogenesis of Piaractus mesopotamicus was investigated under light and transmis-sion electron microscopy. The specimens were captured from their natural environment (Rio Miranda and Rio Aquidauana, Pantanal Matogrossense, Brazil) during April and September. The results were compared with the spermatogenic data of specimens under captivity condition. In both conditions, P. mesopotamicus pre-sented the typical spermatogenesis pattern of the teleost f ishes, showing no significative differences. The spermatozoon was classified as type I, which has a globular head without acrosome, a short middle piece and a long tail constituted only by the flagellum. This type of spermatozoon is considered the basic type in fishes. BIOCEL