SPERM CELLS IN AEOLOSOMA-MARCUSI (ANNELIDA, OLIGOCHAETA)

This work refers to the spermatozoon ultrastructure and the components of late spermatids, in an attempt to elucidate the taxonomic position of Aeolosomatidae family within the Annelida. According to the classi c taxonomy, Aeolosomatidae include species lacking a true clitella and other morphological characteristics present in the clitellate oligoch aeta. These facts led to consider them as enigmatic and questionable w orms, in the bibliography. In recent years, the spermatozoal ultrastru cture knowledge, based on some spermatozoal compounds, and among them, an internal axial road in the acrosome, which appears to be the direc t homologue of oligochaetes, allowed the consideration of the relation ships between oligochaete clittelate species. This small freshwater Ae olosoma marcusi worm, was collected in the Rio de la Plata (Buenos Air es), Argentina, and processed for studies at the light and electron mi croscopy levels. Our results concerning the spermatozoal ultrastructur e revealed the presence of a straight, simple, elongated nucleus; an a crosomal right tube provided with other features; a mitochondrion, and a flagellar axonema in which the 9+2 duplets were surrounded by micro filaments. According to the literature available on this subject, if t he presence of an acrosomal right tube is considered as an indicator o f oligochaetes species, A. marcusi would be considered within them.