Sperm morphology in three marine gastropods from South Western Atlantic Ocean (Caenogastropoda): systematic importance

GIMÉNEZ, J.; ARRIGHETTI, F.; TESO, S.V.; ZABALA, S.; HERMIDA, G.; PENCHASZADEH, P. E.

Antwerp, Bélgica.

Congreso; World Congress of Malacology; 2007

The testis from Caenogastropods typically produces two types of spermatozoa, eusperm and parasperm. The structures of both morphological forms of sperm contribute to understand the reproductive biology and also have been useful to elucidate taxonomic and phylogenetic relationships within gastropods. The following account describes the structure and ultrastructure and the possible systematic importance of euspermatozoa and paraspermatozoa in three species, two form the Volutidae family Adelomelon beckii and Adelomelon ancilla, and the third one Olivancillaria deshayesiana from the Olividae family. Specimens of A. beckii and O. deshayesiana were collected by bottom trawling of Mar del Plata (38°20’S 57°37’W) in 35 to 40 m water depth respectively. A. ancilla were collected in Puerto Madryn (42°42’S 65°06’W), by scuba diving, between 5 and 10 m water depth. For ultrastructural studies small pieces of the testis were fixed in 2% glutaraldheyde with uranyl acetate and lead citrate. For light microscopy small pieces of testis were fixed in Bouin’s solution for using several techniques as hematoxilin-eosin, and Tricromic of Mason and “Periodic Acid Shiff”. In these species, the testis is limited externally by a connective tissue, in contact with the hepatopancreas. Inside of the tubule in the periphery area is possible to see different stages of spermatogenesis, mature sperm are in the middle of this tubules, as also in the spermatic ducts. The Euspermatozoa is characterized by: the presence of an acrosomal vesicle with apical bleb and accessory membrane; the nucleus is long and tubular with the axoneme penetrating the nucleus; midpiece with mitochondrial elements coiled helically around the axoneme, glycolgen piece and short end piece. In A. beckii and A. ancilla was possible to see the paraspermatozoa , vermiform, exhibiting multiple peripheral axonemes and with scattered mitochondria and small dense vesicles.