First record of the blue crab Callinectes exasperatus (Decapoda, Brachyura, Portunidae) for European waters

This paper is the first record of the blue crab, Callinectes exasperatus, in European waters and the first record for this species out of its natural distribution. Due to the similar morphology with Callinectes sapidus, a widely extended invader in the Atlantic, Mediterranean and Pacific waters, the initial determination based on morphological characters was further confirmed by DNA barcode analysis. A possible introduction vector is also discussed.