In this study we describe the functional morphology of Cornu aspersum (Helix aspersa), spermatozoa using light, scanning (SEM) and transmission electron (TEM) microscopies. The studies were performed with sperm located in the frozen hermaphroditic duct. Our results showed that the head presents an elongated conical shape slightly coiled in a corkscrew, with the nucleus partially covered by an acrosome, where an apical vesicle is located at the lateralized apex. This peculiar shape suggests the helical displacement movement of the spermatozoa. The head and the nucleus are slightly larger size compared to those of other gastropod species. The intermediate tract is surrounded by a mitochondrial complex and a glycogen helix. The glycogen helix is coiled helically along the intermediate tract, presenting at least five twists of glycogen helices. The complexity of both the mitochondrial complex and the glycogen helix suggests a high metabolic consumption considering the long period of time until fertilization occurs. Our findings on the detailed characterization of Cornu aspersum spermatozoa, obtained from a frozen hermaphroditic duct can contribute to a better understanding of the functional morphology of sperm and serve as a reference for future studies.

KEY WORDS: Cornu aspersum; Spermatozoa; Frozen hermaphroditic duct; Transmission electron microscopy; Scanning electron microscopy.

FUERTES-RECUERO, M.; ROJO, C.; GARCÍA-CUENCA, I. & FONTANILLAS, J. C. Light microscopic, ultrastructure analysis and functional morphology of Cornu aspersum spermatozoa contained in the frozen hermaphroditic duct. Int. J. Morphol., 41(4):1219- 1227, 2023.