The Winged Mapleleaf, also known as False Mapleleaf, or Hickory Nut Shell, and with the scientific name Quadrula fragosa, is a species of freshwater mussel. It is an aquatic bivalve mollusk in the family Unionidae, the river mussels. It is endemic to the United States.Quadrula fragosa is only located in a few parts of Wisconsin, Minnesota, and Missouri — in the Midwestern United States. It is a federal critically endangered river mussel species.