Anatomy of Oliva elegans Lamarck 1811 and variations in the radula, penis and gonad in four species of Oliva Bruguiere 1789 (Gastropoda: Olividae)

• Main Author: Manalo, Imelda Artillaga
• Format: text
• Language: English
• Published: Animo Repository 2004
• Subjects: Snails; Gastropoda
• Online Access: https://animorepository.dlsu.edu.ph/etd_masteral/3203
• Institution: De La Salle University

A total of 56 olive snails, collected from two different localities: Guinayangan, Quezon off Ragay Gulf, and Lian, Batangas off Talin Bay, were studied anatomically. One species from Ragay Gulf collection Oliva tigridella Duclos 1835, and four species from Talin Bay collection: O. elgans Lamarck 1811, O. reticulata Roding 1798, O. tigridella Duclos 1835 and O. vidua Roding 1798, were identified. Of the five groups, assumed to be four different species, the soft-body anatomy of O. elegans Lamarck 1811 was described to which the other groups were compared. The anatomical study shows that the different species exhibit basically similar structure in their pallial organs, anterior part of digestive system, nerve ring and excretory organ. Differences were noted in the structure and dimensions of the radula. Light microscopy of the radula shows presence of dorsal grooves in the rachidian teeth of the radula in all the groups except in O. elegans. Scanning electron microscopy of the radula, involving one sample per group, shows difference in the anterior profile of the radular rachidian tooth of the different species. They also differ in the lateral view of the rachidian tooth in terms of the curvature and angles formed between the lateral cusps of rachidian tooth and the side flaps. The five groups also show differences in the length and form of the penis. Histology of the penis, involving one sample per group, shows differences in epithelium but basically similar structure of the vas deferens, lined with brush-like aggregate of sperm. Sections of the distal region show short flagellated sperm, while sections of the proximal region show long flagellated sperm cells. Sections of the testis show seminiferous tubules with sperm at different stages of development in O. tigridella from Ragay Gulf. Such structures were not found in the rest of the species from Talin Bay, which show tubules with granular contents and dark-stained nuclei. Sections of the ovary show cluster of eggs in all the samples studied, but remarkably larger eggs were observed in O. tigridella from Ragay Gulf. Taxonomic potentials of the characters studied were discussed.