Gonadal Developments of West African Freshwater Crab (Sudanonautes Africanus, Milne–Edwards, 1869) on the Banks of Asejire Reservoir, Nigeria

Abstract

This paper was on the developmental changes that take place inside the eggs of the fresh water crab (Sudanonuates africanus) from Asejire reservoir in Ibadan Nigerian. The egg consist of two layers a thick outer membrane and a thin inner membrane that encloses the fluid- filled embryonic sac. Development in this species took up to 77 days, after which the free- living juvenile hatching crab emerged from the egg. During developmental the embryo underwent a series of morphological changes that corresponded to the free living larval stages of marine crabs and the yolk mass decreased in size and changed color (from yellow, to orange brown and finally off- white) the eggs remained attached to the pleopods in the females abdominal brood pouch during development and showed a great deal of independence from water embryos developed normally whether they were immersed in water or in air.

Keywords: Crab, Egg, Fecundity, Fresh water, Gonads