Pink Papershell

pink papershell
Scientific Name
Potamilus ohiensis
Unionidae (freshwater mussels) in the phylum Mollusca

Shell is thin, compressed, oval to rectangular with a large dorsal wing. Umbo is not raised above hinge line. Epidermis is shiny, light tan to olive-brown, becomes darker brown with age; light tan juveniles may have a greenish cast; without rays. Inside shell beak cavity is shallow; pseudocardinal teeth thin, small and erect; lateral teeth thin, blade-like and slightly curved; nacre (lining) light purple.

Similar species: Pink heelsplitter has a darker, thicker shell with a deep purple nacre and larger pseudocardinal teeth. Fragile papershell is light yellow with a darker area near the umbo and whitish to whitish-blue nacre, possibly with a pink tinge.


Adult length: 3-6 inches.

Where To Find
image of PInk Papershell Distribution Map

Generally statewide; most common in Gasconade, Osage, Grand, Chariton, Lamine, North Fabius and Salt rivers; uncommon where found.

Shallow areas of medium to large rivers with slow current in silt, mud or sand.

Algae and fine particles of decaying organic matter; extracts nutrients and oxygen from water drawn into the body cavity through a specialized gill called the incurrent siphon; sediment and undigested waste are expelled through the excurrent siphon.


Life Cycle

Males release sperm directly into water. Females downstream siphon sperm into the gill chamber, where eggs are fertilized. Eggs mature into larvae (called glochidia), which discharge into the water and attach to host fish—in this species, the freshwater drum and white crappie. The tiny mussel eventually breaks away and floats to the bottom of the stream, and the cycle repeats.

Mussels are excellent biological indicators of water quality because they are long-lived and relatively immobile, accumulating contaminants in water that can be scientifically analyzed. Because of its relatively thin shell, this species has had little commercial use.

Mussels act as nature's “vacuum cleaners,” filtering and cleansing polluted waters. They are also an important food source for other species in the aquatic environment.

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Similar Species
About Aquatic Invertebrates in Missouri
Missouri's streams, lakes, and other aquatic habitats hold thousands of kinds of invertebrates — worms, freshwater mussels, snails, crayfish, insects, and other animals without backbones. These creatures are vital links in the aquatic food chain, and their presence and numbers tell us a lot about water quality.