COMPARATIVE INVESTIGATIONS ON THE SYSTEMATICS AND TAXONOMY OF EUROPEAN MAJA SPECIES (DECAPODA, BRACHYURA, MAJIDAE)

The systematic validity of the differentiation between the two Europea n spider crabs Maja crispata Risso, 1827 and Maja squinado (Herbst, 17 88) is clarified. The intra- and interspecific variability of morpholo gical characters is examined in juvenile and adult specimens and the r esults are discussed. Due to ontogenetic changes there is neither a si ngle, constant morphological character nor a constant character combin ation which allows a complete separation of all postlarval stages of t he two species. The best diagnostic characters are the median dorsal c arapace spine row combined with a spine located at the basal antennal joint. Multivariate analyses of morphometric characters offered for th e first time appropiate quantitative methods for a complete separation of adults and an almost complete separation of juveniles of the two s pecies which have not been available previously.