- Kingdom: Animalia
- Phylum: Mollusca
- Class: Bivalvia
- Order: Myoida
- Family: Myidae
- Scientific name: Mya arenaria
- Norwegian: vanlig sandskjell
The off-white, yellow, grey or light brown shell can reach a diameter of 15 cm. It is easily distinguished from the blunt gaper by the fact that the shell is not truncated. Growth stages are usually clearly visible.
The sand gaper lives buried in sand or mud from the tidal zone and down to 20 meters. It is often abundant in estuaries and on beaches. It may contract fully into the shell, but usually extends and stretch the siphon through the sand. If you watch carefully on the beach, you may see small water fountains from sand gapers pumping water through the siphon.
It is common both in the northern Atlantic and Pacific oceans. It can be found along the entire Norwegian coast.