THE XERCES SOCIETY FOR INVERTEBRATE CONSERVATION

Aquatic Invertebrates in Pacific Northwest Freshwater Wetlands
An Identification Guide and Educational Resource

Anodonta nuttalliana
(Winged floater)

The Winged Floater is the smallest among our native mussels, and the least common.  It occurs from California to British Columbia.  It prefers muddy or sandy bottoms at low gradients and elevations, especially in coastal watersheds.   Its taxonomy and range, both historical and present,  are little understood, and its host species are unknown.   It is likely effected by the same environmental impacts as other Anodonta species: water diversion, pollution, and competition from non-natives.  

A. nuttalliana can be distinguished from other Anodontids by its thinner shell. The posterior part of its shell extends out as a long flange and is much higher than the anterior part, giving the overall shell a more circular (not oblong) appearance.

Size: xlarge
Identifying feature(s): small, thin shell, somewhat circular in shape
Habitat: soft-bottomed rivers, reservoirs and lakes
Tolerance: moderate