Muricine species with trivaricate shells and more or less expanded varical flanges are generally assigned to Pterynotus, Pterochelus, and Marchia, and are very closely related. Either Pterochelus or Marchia could be treated as of equal rank with, or as a subgenus of, Pterynotus, depending on the interpretation of the worker. Species assigned here to Pterynotus also have a small to moderate-sized fusiform shape, an adherent columellar lip, and a smoothly laminate ventral surface of the varical "wing." The operculum is generally muricoid. The radula is generally muricine, but the central radular tooth exhibits a marked diminution of the intermediate cusps, and the lateral teeth are large and broad-based.