page_title: Quadrula
section_title: Species within the genus Quadrula
hierarchical_section_title: Quadrula / Species within the genus Quadrula
caption_attribution_description: With the general shape of a pistolgrip, the Pistolgrip mussel (Tritogonia verrucosa) can be easily identified. This Pistol grip was found in the Marais des Cygnes River in Kansas. Photo credit: Tim Menard / USFWS.
context_page_description: Quadrula is a genus of freshwater mussels, aquatic bivalve mollusks in the family Unionidae native to rivers of the American Midwest and mid-south. All have thick nacreous shells with well-developed hinge teeth, many also with external shell sculpturing of nodules or lumps.
context_section_description: In 2012, many species classified as Quadrula were moved to Rotundaria and Theliderma based on genetic and morphological evidence.
  Species currently in Quadrula now consist of:
  Quadrula apiculata (Southern mapleleaf)
  Quadrula fragosa (Winged mapleleaf)
  Quadrula nobilis (Gulf mapleleaf)
  Quadrula quadrula (Mapleleaf)
  Quadrula rumphiana (Ridged mapleleaf)
  Quadrula verrucosa (Pistolgrip)
caption: Quadrula verrucosa
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