A review of the Maja squinado (Crustacea: Decapoda: Brachyura) species-complex with a key to the eastern Atlantic and Mediterranean species of the genus

Abstract

The spider crab Maja squinado (Herbst, 1788), reveals considerable morphological variability. This study establishes that Mediterranean populations are separable from those of the Atlantic by morphological and biometrical characters. Consistent, nonclinal morphological character differences of first gonopods and carapace spinulation, and results of multivariate analyses of morphometric measurements justify the recognition of two different species: the Mediterranean Maja squinado (Herbst, 1788) and the Atlantic Maja brachydactyla Balss, 1922. Morphological investigations of Maja capensis Ortmann, 1894—another very similar species from Namibia and South Africa—suggest that its status is rather questionable, due to partial overlap of characters with the Northeast Atlantic species. However, few Maja capensis specimens are available for study and therefore it remains at species rank until more material is available for further study.