Lilac-colored Venus Clam Shell, Chionopsis lilacina

Lilac-colored Venus Clam Shell, Chionopsis lilacina. Shell collected off the beach of Punta Chivato, Baja California Sur, May 2025. Size: 3.1 cm (1.2 inches) x 3.5 cm (1.4 inches) x 1.1 cm (0.4 inches). Collection, photographs and identification courtesy of Colin Campbell, DVM, Punta Chivato.

Phylogeny: The Lilac-colored Venus Clam Shell, Chionopsis lilacina (P. P. Carpenter, 1864), is a bivalve mollusk that is a member of the Veneridae Family of Venus Clam Shells. The genus Chionopsis is one of one hundred and seven genera in this family, and there are twelve species in this genus. They are known in Mexico as Almeja Lila.

Description: Lilac-colored Venus Clam Shells have a circular to ovate profile, being broadly rounded at both ends. They are moderately inflated. The exterior is sculpted with commarginal lamellae, crossed by very fine radial ribs. The lamellae are finely serrated. The interior margin is finely crenulate. The hinge plate is narrow. The exterior is tan in color, with varying darker brown blotches, chevrons, or stripes. The interior is white with varying amounts and shades of rosy-purple. Lilac-colored Venus Clam Shells reach a maximum of 7.1 cm (2.75 inches) in length.

Habitat and Distribution: Lilac-colored Venus Clams are found on sand in the intertidal zone, and to depths of 30 m (98 feet). Some sources extend the maximum depth to 80 m (262 feet). They are a subtropical to tropical Eastern Pacific species that are found in all Mexican waters of the Pacific Ocean with the exceptions that they are absent from the west coast of the Baja Peninsula and from north of Bahía de Los Ángeles, Baja California, in the Sea of Cortez.

Ecology and Behavior: Lilac-colored Venus Clams are suspension feeders, which feed on plankton and suspended organic matter. They are prey for fish, crabs, shorebirds and gastropods. Lilac-colored Venus Clam Shells are gonochoric and reproduce sexually, through broadcast spawning. Their engagement in any type of commensal, parasitic, or symbiotic relationship has not been formally documented. From a conservation perspective they have not been formally evaluated. However, they are fairly common with a relatively wide distribution and should be consider to be of Least Concern.

Synonyms:  Chione purpurissata, Chionopsis olssoni, Puberella lilacina, and Venus crenulata var. lilacina.