Purple Wartyback (Purple Pimpleback)
Shell is thick, heavy, nearly round, compressed (in shells from small rivers) to inflated (from large rivers) and covered with many bumps; anterior end rounded, posterior end squared off. Umbo is slightly raised above hinge line. Epidermis is yellowish-brown to greenish-brown, becomes darker with age; greenish rays may be present in juveniles. Inside shell beak cavity deep and wide; massive pseudocardinal teeth, widely spaced and deeply grooved; lateral teeth short and straight or slightly curved; nacre (lining) deep coppery-purple.
Similar species: Pimpleback and wartyback are less massive and less compressed, have white nacre and smaller pseudocardinal teeth. Mapleleaf has a definite sulcus, white nacre and smaller pseudocardinal teeth.