Shelled Aquatic Macroinvertebrates

Snails

Snails belong to the class Gastropoda, within the phylum Mollusca, and are identified by a single shell often formed into a spiral or coil. Five families of snails are commonly found in Utah.

Family	Picture	Description	Habitat
Hydrobiidae (spring snails)		1-8 mm. Opening on right side of spiral. Shell is smooth with an operculum. Color is uniform, light to dark brown.	Found in springs and rivers throughout Utah
Lymnaeidae (pond snails)		10-55 mm. Opening on right side of spiral. Shell is thin and generally has an elongate spire, no operculum. Color varies with species.	All freshwater habitats
Physidae (pond snails)		8-25 mm. Opening on left side of spiral, has glossy shell with raised spire and large aperture and no operculum. Color varies with species.	Ponds, rivers
Planorbidae (orb snails)		2-25 mm. No obvious spiral, coil is fat, no operculum. Color varies with species.	Wetlands, ditches
Thiaridae (red-rimmed melanoides)		5-50 mm. Shell is at least twice as long as it is wide. Shell is light brown with many reddish-brown spots.	Invasive, found in warm springs
Valvatidae (round-lipped snail)		1-3 mm. Opening on right side of spiral. Spiral is subdiscoidal. Aperture is circular, with an operculum. The outermost layer is mostly green.	Streams and lakes in northern Utah
Viviparidae (Chinese mystery snails)		Up to 60 mm. Black pigmentation rims the entire lip, shell is smooth, thin and strong in structure. Color is uniform light to dark olive-green color	Found partially buried in mud of lakes, ponds, ditches, or slow moving streams.

Family	Picture	Description	Habitat
Corbiculidae (Asiatic Clam)		Thick, oval shell. Concentric striae feel rough when scratched. Length 10-20 mm, up to 50 mm. Yellow, green, or brown in color.	Invasive- burrows in sediment of freshwater lakes and rivers.
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)		Shells 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 andGonidea angulata.  They are found in large rivers and reservoirs in the Great Basin.
Dreissenidae (Zebra and Quagga Mussel)		Distinct triangular shaped shell, striped patterns. Exotic species from Eastern Europe. Up to 50 mm in length	Invasive- All aquatic habitats
Pisidiidae (Fingernail Clam)		Shells are thin, smooth, and generally oval. Yellow, green or white in color. Less than 25 mm in length, generally less than 10 mm.	All aquatic habitats