Development of the Larval Stages of the Blue Swimming Crab Portunus pelagicus L. (Portunidae : Decapoda : Crustacea)

Abstract

The four zoeal stages and megalopa of P. pelagicus were reared in culture and are described. Each appendage or structure is described showing the changes that occur during the zoeal phase. P. pelagicus larvae have similar types and location of setae as the larvae of P. spinicarpus. The positions of the chromatophores in the zoeal stages are described. The megalopa has the same types of setae as the zoea with the addition of two types of modified serrate setae. The zoea has no gastric mill and the capture and mechanical breakdown of the prey is the function of the mouthparts: the labrum, mandibles, maxillules and maxillae; and the serrated setae in the curve of the telson. The mouthparts of the megalopa are composed of the same appendages as in the zoea with the incorporation of the first, second and third maxillipeds. There are discrepancies between the descriptions in the present study and that of Prasad and Tampi (1953) whose second and third zoea and megalopa were obtained from the plankton. P. pelagicus larvae are compared with those of Scylla serrata to see if they could be distinguished, morphologically.