title: Comparison of the spermatozoan morphology of Isognomon bicolor and Isognomon alatus (Mollusca, Bivalvia, Isognomonidae).
abstract: In this study we used transmission and scanning electron microscopy to examine the spermatozoan structure of Isognomon bicolor and Isognomon alatus. The spermatozoa of both species were of the primitive or ect-aquasperm type. The acrosomal morphologies were essentially similar but the top of the acrosomal vesicle in I. bicolor sperm had a slightly flattened edge whereas the apex of the acrosomal vesicle of I. alatus sperm had a rounded outline. This difference suggested that acrosomal morphology could be an important character for taxonomic differentiation. In the present work, the results demonstrated that the gamete ultrastructure of the two distinct species I. alatus, from Panama, and I. bicolor, from the southeastern region of Brazil, were similar to the other studied species of the superfamily Pterioidea.
authors.affiliation: Departamento de Biologia Celular, Instituto de Biologia, Universidade Estadual de Campinas (UNICAMP), Campinas, SP, Brazil.
authors.forename: G O
authors.initials: GO
authors.lastname: Introíni
authors.forename: C A
authors.initials: CA
authors.lastname: Magalhães
authors.forename: H
authors.initials: H
authors.lastname: Fortunato
authors.forename: S M
authors.initials: SM
authors.lastname: Recco-Pimentel
mesh_terms: D000177:Acrosome / Q000648:ultrastructure*; D000818:Animals; D049872:Bivalvia / Q000145:classification* / Q000166:cytology* / Q000502:physiology; D001938:Brazil; D022162:Cytoplasmic Vesicles / Q000648:ultrastructure; D008297:Male; D008855:Microscopy, Electron, Scanning; D046529:Microscopy, Electron, Transmission; D013045:Species Specificity