The Knobbed porgy, Calamus nodosus, is an ocean-going species of gamefish of the Sparidae (Bream/Porgy family). They are only found in the western portion of the tropical Atlantic Ocean, where they are often caught with trawling nets or by angling, and used as food. The Knobbed porgy was named by John Randall and David Caldwell as part of a 1966 review of the Calamus genus, which was published in the academic journal Science. Randall and Caldwell also described three other species of Calamus in the paper.