24. Morphology and Anatomy of the Pearl Oyster, Pinctada margaritifera in the Red Sea: A Case Study from Dungonab Bay, Sudan

The black-lip-mother of pearl oyster Pinctada margaritifera has special economic value in Dungonab Bay (Sudan). It has been cultivated in the area for a long time as it has the advantage of having a definite spawning season starting at the end of June and continuing throughout July and August. Morphological and anatomical studies of this oyster are given in this piece of work including description of external feature of the shells and internal organs such as the mantle, the gills, digestive system, circulatory system, nervous system, excretory system and the reproductive organs. Morphological and anatomical differences between P. margaritifera on one hand and both the European oyster, Ostrea edulis, and the American oyster, Crassostrea gigas, are presented. These differences included the presence of a long hinge on one side of the umbo in P. margaritifera an its absence in both O. edulis and C. virginica; both valves in P. margaritifera are moderately convex and neither of them can be easily distinguished, unlike O. edulis, and C. gigas; the mantles have free edges in P. margaritifera and the omission of pedal ganglia in both C. gigas and O. edulis due to the absence of a foot in these two species.