Ultrastructure of the optic gland of the squid <i>Sepiotheutis sepioidea</i> (Cephalopoda: Loliginidae)

Abstract

1 describe the fine structure of the optic gland (OG) in the tropical squid Sepiotheutis sepioidea at different sexual maturity stages. Squids were collected in Mochima National Park, Venezuela (lO° 20' 22 "- 10° 24' N; 64° 19' - 64° 22' W). Morphometric characteristics and the development of reproductive organs at different sexual maturity stages (female n = 101; male n = 105), were significantly different (ANOVA, p < 0.001). The female gonadal index mean (GI = (ovary weight I body weight) x 100) between 0.1 - 2.95 %, and the male GI mean (GI = (testieule weight I body weight) x 100) oscillated between 0.22 - 1.38 %. The OG are a pair of oval organs loeated at the posterior edge of the optic traet of the cephalopod brain. The OG showed the same eellular types described in other cephalopods, with slight djfferences. The secretory cells in young indjviduals present a dendritic profile with thin cytoplasmic processes, numerous circular mitochondriae with tubular crests and abundant ribosomes. At the last stage of maturity the secretory cells contain rough endoplasmic retieulum in the form of dilated cisternae, with an active Golgi apparatus, secreting electron dense granules. Mitochondriae are scarce and lipofuchsin granules show an íncrease in síze. Secretory cell nucleus length and organelle abundance showed oseillations associated with the life cycJe