Small Lucine  Shell, Divalinga perparvula

Small Lucine Shell, Divalinga perparvulaa. Shell collected off the beach of Punta Chivato, Baja California Sur, June 2025. Size: 1.9 cm (0.7 inches) x 1.4 cm (0.6 inches) x 0.5 cm (0.2 inches). Collection, photographs and identification courtesy of Colin Campbell, DVM, Punta Chivato.

Small Lucine Shell, Divalinga perparvula. Shell collected off the beach of Punta Chivato, Baja California Sur, June 2025. Size: 2.0 cm (0.8 inches) x 1.9 cm (0.7 inches) x 0.5 cm (0.2 inches). Collection, photographs and identification courtesy of Colin Campbell, DVM, Punta Chivato.

Phylogeny: The Small Lucine Shell, Divalinga perparvula (Dall, 1901), is bivalve mollusk of the Lucinidae Family of Lucine Shells, and the Lucininae subfamily. The Divalinga Genus is one of ninety-seven genera in the Lucinidae Family, and there are nine species in the Divalinga Genus. They are known in Mexico as Lucina Pequeña.

Description: The Small Lucine Shell has a round to ovate outline and an inflated profile. The beak is prominent. The exterior of the shell is sculpted by several strong, concentric, chevron ridges, as well as commarginal growth lines. The shell is cream to light orange in color. Small Lucine Shells reach a maximum of 2.3 cm (0.9 inches) in length.

Habitat and Distribution: Small Lucine Shells are found in sandy substrates. They live at depths of 7 m (22 feet ) to 60 m (197 feet). They are a subtropical to tropical Eastern Pacific species.  Small Lucine Shells are found in all Mexican waters of the Pacific Ocean with the exception that they are absent from north of Bahía Kino, Sonora, in the Sea of Cortez, and from north of Magdalena Bay, Baja California Sur, along the central and northwest coasts of the Baja Peninsula.

Ecology and Behavior: Small Lucine Shells are suspension feeders that feed on plankton and other suspended organic matter, as well as chemosymbiotic. Small Lucine Shells host symbiotic sulfur-oxidizing bacteria in specialized gill cells called bacteriocytes. They live in environments with sulfide-rich sediments. The Small Lucine 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, Small Lucine Shells can digest their symbionts as food. They are preyed upon by crabs, fish, 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 perparvula, and Lucina pisum.