Belcher’s Prickly Cockle Shell, Phlogocardia belcheri

Belcher’s Prickly Cockle Shell, Phlogocardia belcheri. Size: 4.3 cm (1.7 inches) x 3.9 cm (1.5 inches). Shell collected from within the estuary of the Magdalena Bay complex, Baja California Sur, October 2018. Identification courtesy of Bob Hillis, Ivins, Utah.

Belcher’s Prickly Cockle Shell, Phlogocardia belcheri. Size: 4.3 cm (1.7 inches) x 3.9 cm (1.5 inches). Shell collected from within the estuary of the Magdalena Bay complex, Baja California Sur, October 2018. Identification courtesy of Bob Hillis, Ivins, Utah.

Phylogeny: Belcher’s Prickly Cockle, Phlogocardia belcheri (Broderip and G.B. Sowerby I, 1829), is a bivalve mollusk that is a member of the Cardiidae Family of Cockles and True Cockles. The genus Phlogocardia is one of forty-nine genera in this family, and this is the only species in this genus. This species was named in honor of Admiral Sir Edward Belcher, who commanded the scientific circumnavigation of the globe aboard the HMS Sulphur in the 1830’s. Several species of fish, mollusk, plant, reptile, and seabird are named in his honor, as-well-as several geographic locations.

Description: Belcher’s Prickly Cockle Shell is almost circular in outline, with a moderately high beak. The outside of the shell is adorned with radial ridges, which become saw-toothed toward the posterior end. The shell exterior is white, with pastel yellow, orange, brown, or pink sections. The interior is white, cream, or light yellow. Belcher’s Prickly Cockle Shells reach a maximum of 5.4 cm (2.1 inches) in length and 4.4 cm (1.7 inches) in height.

Habitat and Distribution: Belcher’s Prickly Cockles are found on and within sand and mud substrates at depths between 14 m (45 feet) and 200 m (650 feet). They are a subtropical/tropical Eastern Pacific species that are found in all Mexican waters of the Pacific Ocean with the exception that they are absent from north of Cedros Island, Baja California, along the central and northwest coasts of the Baja Peninsula and north of Bahía Santa Ines, Baja California Sur, in the Sea of Cortez.

Ecology and Behavior: Belcher’s Prickly Cockles are suspension feeders that feed primarily on plankton and other suspended organic matter. They are eaten by fish, sea stars, crabs, and gastropods. They are gonochoric and reproduce sexually, through broadcast spawning, with external fertilization. Their engagement in any type of commensal, parasitic, or symbiotic relationships has not been formally documented. From a conservation perspective the Belcher’s Prickly Cockle has not been formally evaluated. However, they are fairly common with a relatively wide distribution and should be considered to be of Least Concern.

Synonyms: Cardium belcheri, Trachycardium (Phlogocardia) belcheri, and Trachycardium belcheri.