Definition of Polypterus
: the type genus of Polypteridae that comprises primitive fishes of the larger rivers of tropical Africa having an elongate body covered with rhombic enameled scales, a dorsal fin reduced to a series of finlets, pectoral fins taking the form of a rounded lobe supported on a short arm, and an air bladder functioning as an accessory breathing organ — see bichir, erpetoichthys
