Size: Adult size from 4.75 to 7.25 inches.
Shape: Elliptical; L:H ratio close to, or exceeding, 2.0. Dorsal posterior margin may be compressed and formed into slight wing, but this trait is variable. Valves laterally inflated, thin, and fragile.
Beaks: Low; rarely project above the hinge line.
Periostracum: Yellowish, yellowish-brown, brown, or black. Some specimens may have a tinge of green. Periostracum is usually shiny, and growth lines are usually evident.
Hinge Teeth: None.
Nacre: White or bluish-white, sometimes pinkish toward the central portion of the nacre and iridescent toward the posterior end.
For a discussion on Anodonta taxomony, please refer to the original publication, The Freshwater Mussels of the Pacific Northwest.