Toxolasma parvus (Barnes, 1823)
Other common names: None.
Key characters: Small shell, usually no more than an inch long, elliptical or cylindrical, dark green or brown, with a clothlike texture.
Description: Shell small, elliptical or cylindrical, relatively solid, and inflated. Anterior and posterior ends rounded. Umbos inflated and slightly elevated above the hinge line. Beak sculpture consists of five or six distinct angled ridges. Surface of the shell with a clothlike texture, dark green, brown, or dark brown and rayless. Length to 1.5 inches (3.8 cm).
Pseudocardinal teeth thin, elevated, compressed, and serrated; two in the left valve, one or two in the right. Lateral teeth long, thin and straight; two in the left valve, one in the right. Beak cavity moderately deep. Nacre silvery or bluish white and highly iridescent.
Habitat: Ponds, lakes, and creeks to large rivers in mud, sand, or fine gravel.
Status: Widespread and locally abundant.