Histological Description of Oogenesis in Chiton virgulatus (Mollusca: Polyplacophora)

• Published in: International journal of morphology 2014-06, Vol.32 (2), p.608-613
• Main Authors: Vélez-Arellano, Nurenskaya, Shibayama, Mineko, Ortíz-Ordoñez, Esperanza, Silva-Olivares, Angélica, Arellano-Martínez, Marcial, García-Domínguez, Federico
• Format: Article
• Language: English
• Subjects: ANATOMY & MORPHOLOGY
• ISSN: 0717-9502; 0717-9502
• DOI: 10.4067/S0717-95022014000200038

This paper describes the oogenesis of Chiton virgulatus, based on histological observations under transmission and scanning electron microscopy. Three oocyte types were identified: i) previtellogenic oocytes with a mean diameter of 50±20.5 µm, surrounded by elongated follicular cells of approximately 5 µm, ii) immature vitellogenic oocytes with a mean diameter of 113±15.3 µm and small cytoplasmic projections denoting the onset of the oocyte hull development; adjacent to each projection are pores approximately 0.7 µm in diameter, and iii) mature vitellogenic oocytes with a mean diameter of 146±24.8 µm; the oocyte cytoplasmic projections grow and its apical zone becomes trident-shaped; follicular cells adopt a bulbous shape due to the growth of the elongation and can reach up to 20 µm in length. The morphology and ultrastructure of the projections of the mature vitellogenic oocyte, as well as the size of pores at their base, are specific to C. virgulatus; therefore, these features could be used in taxonomic or fertilization studies.