Medionidus is a genus of freshwater mussels, aquatic bivalve mollusks in the family Unionidae.
Species within the genus Medionidus Medionidus acutissimus (Alabama moccasinshell) Medionidus conradicus Medionidus parvulus (Coosa moccasinshell) Medionidus penicillatus (gulf moccasinshell) Medionidus simpsonianus (Ochlockonee moccasinshell) Medionidus walkeri