Lenticular Semele Shell, Semele lenticularis

Lenticular Semele Shell, Semele lenticularis. Shell collected off the beach in Punta Chivato, Baja California Sur, December 2024. Size: 2.2 cm (0.9 inches) x 2.0 cm (0.8 inches) x 0.4 cm (0.2 inches). Collection, photographs and Identification courtesy of Colin Campbell, DVM, Punta Chivato, Baja California Sur.

Lenticular Semele Shell, Semele lenticularis. Shell collected off the beach in Punta Chivato, Baja California Sur, December 2024. Size: 3.3 cm (1.3 inches) x 3.0 cm (1.2 inches) x 0.7 cm (0.3 inches). Collection, photographs and Identification courtesy of Colin Campbell, DVM, Punta Chivato, Baja California Sur.

Phylogeny: The Lenticular Semele Shell, Semele lenticularis  (G.B. Sowerby I, 1833), is a bivalve mollusk in the Semelidae Family of Furrow Shells. The Semele Genus is one of fifteen genera in the Semelidae Family, and there are fifty-seven species in the Semele Genus. Semele was the mother of Dionysus in Greek mythology. The species name lenticularis comes from the Latin words meaning “lentil-like” or “lens-shaped”.

Morphology: Lenticular Semele Shells have an ovate or elliptical outline and a moderately inflated profile. The shells are thinly constructed. The anterior end may be slightly longer than the posterior. Both ends may be broadly rounded, or the posterior may be truncate (appearing chopped off). Lenticular Semele Shells are sculpted with fine commarginal and radial striae. The exterior is white to cream colored, often with reddish specks or chevrons. The periostracum is dull and tan or olive in color. The interior is white, often with a yellow blush. Lenticular Semele Shells reach a maximum of 3.4 cm (1.3 inches) in length.

Habitat and Distribution: Lenticular Semele Shells are found in sand or sandy rubble. They live in the intertidal zone and to a depth of 44 m (144 feet). Lenticular Semele Shells are a subtropical to 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 Laguna Ojo de Liebre, Baja California Sur, along the central and northwest coasts of the Baja Peninsula.

Ecology and Behavior: Lenticular Semele Shells are suspension feeders that feed primarily on plankton and suspended organic matter. In turn, they are prey for gastropods, sea stars, octopuses, and crabs. They are gonochoric and reproduce sexually, through broadcast spawning, with external fertilization. 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 considered to be of Least Concern.

Synonyms: Amphidesma lenticulare, Amphidesma ventricosum, and Semele (Semele) lenticularis.