Elegant Lucine Shell, Codakia distinguenda

Elegant Lucine Shell, Codakia distinguenda. Size: 7.3 cm (2.9 inches) x 6.4 cm (2.5 inches).  Shell collected off the beach at Cabo Real, Baja California Sur, October 2022.  Identification courtesy of Bob Hillis, Ivins, Utah.

Phylogeny: The Elegant Lucine, Codakia distinguenda (Tyron, 1872), is a bivalve mollusk that is a member of the Lucinidae Family of Lucine Shells. The genus Codakia is one of ninty-seven genera in this family, and there are eight species in this genus. They are also known as the Distinguished Lucine and in Mexico as Lucina Elegante.

Description: The Elegant Lucine shell is sturdy, with a round outline. It is slightly inflated and has strong hinge teeth. The exterior surface is marked with narrow radiating lines, which cross fine concentric ribs. The shell has a white exterior. The interior is white, with a yellow center, and a reddish-pink border. Elegant Lucine Shells reach 15 cm (5.9 inches) in length and 13 cm (5.2 inches) in width.

Habitat and Distribution: Elegant Lucines are found buried in mud or muddy sand, in shallow water and to depths up to 50 m (165 feet). They are a subtropical to tropical Eastern Pacific species. In Mexican waters they range from Alijos Rocks, Baja California Sur, to Guatemala, including the  Revillagigedo Islands. They are found throughout the Gulf of California.

Ecology and Behavior:  Elegant Lucines are suspension feeders that feed primarily on planktonic algae and suspended organic matter. They reside in high sulfide environments and are capable of producing their own nutrients through a symbiotic relationship with sulfur-oxidizing bacteria that are found on the clam’s gill filaments. This process is known as chemosymbiosis. They are gonochoric and reproduce sexually, through broadcast spawning, with external fertilization.  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: Codakia colpoica, Codakia pinchoti, and Lucina (Codakia) distinguenda.