The heart cockles with well developed spines are sometimes considered a subspecies or even a full species, Corculum dionaeum. However, the World Register of Marine Species lists C. dionaeum as a synonym of C. cardissa. These attractive little bivalves are not especially rare at Kwajalein Atoll in lagoon patches of Halimeda algae at depths of about 8 to 30m.
Upper side.
Lower side of above clam.
Upper side.
Lower side of above clam.
Upper side.
Lower side of above clam.
Uppe side.
Lower side of above clam.
Occasionally, it is seen in a smooth variety.
Created 13 February 2019
Updated 13 January 2022