Ivory Lucine Shell, Divalinga eburnea

Ivory Lucine Shell, Divalinga eburnea. Shell collected off the beach of in the greater Los Cabos area, Baja California Sur, March 2008. Size: 2.5 cm (1.0 inch) x 2.6 cm (1.0 inch).

Phylogeny: The Ivory Lucine Shell, Divalinga eburnea (Reeve, 1850), is bivalve mollusk of the Lucinidae Family of Lucine Shells. The genus Divalinga is one of ninety-seven genera in this family, and there are nine species in this genus. They are known in Mexico as Lucina Marfil.

Description: The Ivory Lucine Shell has a round profile with a low beak. The exterior of the shell surface resembles white porcelain and is sculpted by several strong, concentric ridges, crisscrossed by finer, curving, transverse lines. The shell has a uniform white coloration. Ivory Lucine shells reach a maximum of 3.1 cm (1.2 inches) in height and 3.1 cm (1.2 inches) in height.

Habitat and Distribution: Ivory Lucine Shells are found in mud substrates in the intertidal zone, and to depths up to 100 m (330 feet). They are a subtropical to tropical Eastern Pacific Species that are found in Mexican waters of the Pacific Ocean from Bahía de San Bartolomé, Baja California Sur south to Guatemala. They are found throughout the Sea of Cortez.

Ecology and Behavior: Ivory Lucine Shells are suspension feeders that feed primarily on plankton and other suspended organic matter. Ivory Lucine Shells host symbiotic sulfur-oxidizing bacteria in specialized gill cells called bacteriocytes.  They live in environments with sulfide-rich sediments. The shell pumps sulfide-rich water over its gills to provide the bacteria with sulfur and oxygen. These endosymbiotic bacteria then use these substrates to fix carbon into organic compounds, which are then transferred to the host as nutrients. If they lack sufficient food sources,  Ivory Lucine Shells can digest their symbionts as food. Ivory Lucine Shells are preyed upon by fish, crabs, and gastropods. 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: Divaricella columbiensis, Divalinga lucasana, and Lucina eburnea.