DESCRIPTION OF LARVAL DEVELOPMENT OF MAJA SQUINADO (DECAPODA, BRACHYURA, MAJIDAE) AND REVISION OF M. BRACHYDACTYLA LARVAE COLLECTED FROM PLANKTON AND REARED UNDER LABORATORY CONDITIONS.

The morphology of the different larval stages (zoea I, zoea II and megalopa) of the majid crab Maja squinado (Herbst, 1788) reared under laboratory conditions is described. The first zoea were obtained from an ovigerous female collected in the Mediterranean Sea in April 2006. The description of M. brachydactyla Balss, 1922 larvae is also revised, both from individuals reared in laboratory conditions, and collected from plankton samples in the English Channel. The larval stages of M. squinado are morphologically very similar to those of the Atlantic species M. brachydactyla, being the differences found between both larval types insufficient to support the differentiation of the two species only using adult morphology. The specimens of M. brachydactyla obtained from the wild are very similar to those reared in laboratory conditions. It is possible that this low variability in the morphological characteristics might be a consequence of the abbreviated larval development which is characteristic among the Majoidea. Furthermore, the morphology of the zoeae and megalopa stages of both M. squinado and M. brachydactyla described herein are compared with previous descriptions of species of the genus Maja, including M. brachydactyla (described as M. squinado).