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

GIMENEZ, JULIANA; ARRIGHETTI, FLORENCIA; TESO, VALERIA; ZABALA, MARÍA SOLEDAD; HERMIDA, GLADYS; PENCHASZADEH, PABLO

Bélgica

Congreso; 16th World Congress of Malacology (WCM); 2007

UNITAS MALACOLOGICA

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 from 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 (38º20’S 57º37´W) in 35 to 40 m and 8 to 12 m water depth respectively. A. ancilla were colected in Puerto Madryn, (42º 42’ S 65º 06’ W), by scuba diving, between 5 and 10 m water depth.For ultraestructural studies small pieces of the testis were fixed in 2% glutaraldehyde, were embedded in Spurr´s epoxy resin and ultra-thin sections were cut and stained 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 Tricrmic of Masson 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 the 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, glycogen piece and short en 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.