washboard
- kingdom: Animalia
- phylum: Mollusca
- class: Bivalvia
- order: Unionida
- family: Unionidae
- genus: Megalonaias
- species: Megalonaias nervosa
- Chattahoochee
Florida- Rock Island
Illinois- Davenport
Iowa- Chetopa
Kansas- Coraopolis
Pennsylvania
United States