Key to Aquatic Macroinvertebrates in Utah-Large Mussels/Clams

There are two families of large mussels native to Utah, Margaritifieridae and Unionidae.  The family Corbiculidae can also be found in Utah, but is a non-native mussel.

Family Picture Description Habitat

Corbiculidae

Asiatic Clam

INVASIVE

Thick, oval shell.

Concentric striae feel rough when scratched.

Length 10-20 mm, up to 50 mm

Yellow, green, or brown in color.

Burrows in sediment of freshwater lakes and rivers.  Corbiculidae has been collected throughout Utah from Lake Powell to  Box Elder County

Margaritiferidae

Western River Pearl Mussel

Shells are thick, heavy, and typically oblong. Shell striae are concentric. 

Length to 160 mm, Height to 70 mm, Diameter to 40 mm

Shell color is brown, black to olive green. 

Historically occurred in streams in the Wasatch Mountains.  This family has not been collected in Utah since 1930.  Is common in the Snake River drainage and the Humbolt River basin.

Unionidae

Freshwater Mussel


Shell vary from thick to thin.  They are generally elongated and never round. 

Length to 100 mm, Height to 60 mm, Diameter to 35 mm

Shell color is green, yellow or brown.

Two genera occur in Utah - Anodonta and Gonidea angulata.  They are found in large rivers and reservoirs in the Great Basin

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