Dreissena polymorpha (Pallas, 1771)
Other common names: None.
Key characters: Relatively small, triangular, and elongate shells with alternating cream and brown bands on the surface.
Similar species: Dark falsemussel. See Marsden (1992) for information on distinguishing between these two species.
Description: Adults with a distinctively shaped, elongate, triangular, and inflated shell. Highly variable with respect to color as its scientific name polymorpha (many forms) indicates. Most are white or cream-colored with jagged lateral brown to black stripes or bands, which give the species its common name. Some have longitudinal bands, and all-cream or all-black individuals have been found. Length to 1.5 inches (3.8 cm).
No pseudocardinal or lateral teeth. A small shelf or septum present at the anterior end forming a moderately deep beak cavity. Nacre white and somewhat polished.
Habitat: Lakes and streams of all sizes; attaches to rocks, freshwater mussels, or almost any hard surface by gluelike fibers called byssal threads.
Status: Introduced into the Great Lakes from eastern Europe and rapidly spreading throughout the United States.
Distribution: For current information about zebra mussels, click here.