Noun | 1. | family Portunidae - swimming crabs arthropod family - any of the arthropods Brachyura, suborder Brachyura - an order of crustaceans (including true crabs) having a reduced abdomen folded against the ventral surface swimming crab - marine crab with some legs flattened and fringed for swimming genus Portunus, Portunus - type genus of the family Portunidae genus Ovalipes, Ovalipes - a genus of Portunidae Callinectes, genus Callinectes - New World blue crabs |