Atlantic Ribbed Mussel (Geukensia demissa Dillwyn, 1817): Shadow Reactive

The adult Atlantic Ribbed Mussel is 2-4 inches long and has distinctive radial, bifurcating ribs. Its white exterior is usually obscured by the olive or brownish periostracum. The irridescent interior is bluish white, perhaps with a purple or purplish-red posterior end.

Mussels eat plankton. Some mussels filter 10 gallons (4.5 litres) of seawater per day to obtain enough food.

Geukensia usually lives in the mud in salt marshes which have twice daily tidal risings and fallings of the brackish water. The Ribbed Mussel is exposed to air more than it is submerged in water, making it one of the most terrestrial of all North American bivalves. When exposed to the air, the mollusk gaps open its shell a little and breathes air. When a shadow falls across the creature it closes its shell, and other nearby mussels, feeling the vibration from the closing, close their shells too.

The bivalve is found from the Gulf of St. Laurence to northeast Florida, and in the San Fransisco Bay. This mussel is edible.

Notes

The shells pictured here were found at Myrtle Beach, South Carolina.
For more information on the Atlantic Ribbed Mussel see:
- R. Tucker Abbott, American Seashells.
- Bob Lollo, Seashore Identifier.
- Andrew J. Martinez, Marine Life of the North Atlantic.
- Edward Ruppert, Seashore Animals of the Southeast.
Classification: Family Mytilidae; Superfamily Mytiloidea; Order Mytiloida; Superorder Isofilibranchia; Subclass Pteriomorphia.
Scientific nomenclature is subject to change, due to ongoing research. The above classification corresponds to that published by the Conchologists of America, Inc.
Digital formatting is by Jonathan Mitchell.

Atlantic Ribbed Mussel:A Breathing Bivalve

Notes

Atlantic Ribbed Mussel:
A Breathing Bivalve