(Quadrula pustulosa) Lea, 1831
Juvenile and Adult Pimpleback mussels

U.S. Army Corps of Engineers

Other Common Names:
Warty pigtoe; Wartyback
Found in mud, sand, or gravel in moving waters of medium to large rivers.
Up to 4 inches (10.2 cm).
Outer Shell Color:
Yellowish-green to light brown in younger mussels and becomes chestnut to dark brown as the shell matures.
Inner Shell Color:
Pearly white with rainbow coloration on the end farthest from where the shell halves meet.
Shell Thickness:
Shell Outline:
Round. The end closest to where the two halves meet is round, opposite end is somewhat truncated. The top of the shell is straight, while the bottom is curved.
Shell Surface:
The end closest to where the two halves meet is smooth, and the opposite half is covered with bumps.
Scientific Description:
Shell brown or yellow with one or more broad, green rays on each beak. Heavy, subcircular, nonangular shell. Juvenile shell lacks sculpture. Adult shells have varying numbers of rounded tubercles in no predictable pattern. Incurrent papillae dendritic (small, branched). Subdivided excurrent aperture.
Similar Looking Mussels:
Orange-foot Pimpleback, Purple Wartyback, Wartyback, Mapleleaf.
Host Fish:
Several widespread, common fishes, mostly catfishes.
Widespread and relatively common.
Minnesota State Listing:
Federal Listing:

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