Panama Thorny Cockle Shell, Dallocardia senticosum

Panama Thorny Cockle Shell, Dallocardia senticosum.Shell collected off the beach at Km 26, Cero Colorado, Baja California Sur, March 2010. Size: 2.6 cm (1.0 inch) x 2.6 cm (1.0 inch).

The Panama Thorny Cockle, Dallocardia senticosa (G.B. Sowerby I, 1833), is a bivalve mollusk that is a member of the Cardiidae Family of Cockles and True Cockles.  The shell is inflated with a circular profile with the exterior having numerous radiating ribs, which, at both ends, these ribs extend to the margins as small spines. These shells are whitish with reddish or pink blotches. The inside is white with pink at the hinge. The Panama Thorny Cockles reach a maximum of 6.0 cm (2.4 inches) in length and 5.7 cm (2.2 inches) in height.

The Panama Thorny Cockle is found over and within sand and mud substrate at depths up to 91 m (300 feet). They are suspension feeders that filter plankton and fine detritus from the surrounding water. They are found throughout the Sea of Cortez and south to Peru, however that have not been documented on the West Coast of Baja.

Synonyms include Cardium radula, Cardium rostrum, Cardium senticosum, Dallocardia radula, and Trachycardium senticosum.