Pearly Jingle Shell, Anomia peruviana

Pearly Jingle Shell, Anomia peruviana. Shell collected off the beach of Punta Chivato, Baja California Sur, March 2025. Size: 4.1 cm (1.6 inches) x 3.7 cm (1.5 inches) x 0.8 cm (0.3 inches). Collection, photographs and identification courtesy of Colin Campbell, DVM, Punta Chivato. Note that the shell has a very prominent three muscle attachment.

Pearly Jingle Shell, Anomia peruviana. Shell collected off the beach of Punta Chivato, Baja California Sur, March 2025. Size: 4.4 cm (1.7 inches) x 2.8 cm (1.1 inches) x 1.2 cm (0.5 inches). Collection, photographs and identification courtesy of Colin Campbell, DVM, Punta Chivato.

Pearly Jingle Shell, Anomia peruviana. Shell collected off the beach of Punta Chivato, Baja California Sur, March 2025. Size: 5.7 cm (2.2 inches) x 4.4 cm (1.7 inches) x 1.2 cm (0.5 inches). Collection, photographs and identification courtesy of Colin Campbell, DVM, Punta Chivato.

Phylogeny: The Pearly Jingle Shell, Anomia peruviana (d’Orbigny 1846), is a bivalve member of the Anomiidae Family of Jingle Shells. The genus Anomia is one of nine genera in this family, and there are ten species in this genus. This species is also known as the Peruvian Jingle Shell and the Peruvian Oyster. The word anomia is related to the Greek word for “irregular,” referring to the shell’s shape.

Description: The Pearly Jingle Shell has an irregular circular, ovate, or trigonal outline. The shell  is thin, to the point of being translucent. The valves are unequal. The right (lower) valve is smaller than the left, is flat, and has a hole (foramen) through which the byssal plug attaches the shell to the substrate. The left valve is convex, and sometimes sculpted by weak to strong radial ribs. The left valve is usually the one found washed up on the beach. The exterior color is yellowish brown to yellowish green. The interior is smooth and may be white, yellow, orange or green. The interior of the left valve is iridescent and has three distinct muscle attachment scars. Pearly Jingle Shells reach a maximum of 8.5 cm (3.3 inches) in width.

Habitat and Distribution: Pearly Jingle Shells are found attached to rocks, dead shells, and other hard substrates from the intertidal zone to a depths up to 110 m (361 feet). They are a temperate to tropical Eastern Pacific species that are found in Mexican waters of the Pacific Ocean along the entire west coast. They are also found throughout the Sea of Cortez. There is also some evidence that this species has been introduced to the tropical Western Atlantic, where it is now considered to be an invasive species.

Ecology and Behavior:  Pearly Jingle Shells are suspension feeders that feed primarily on planktonic algae. They are gonochoric and reproduce sexually, through broadcast spawning, with external fertilization. There is no mention in the available literature of them engaging in any types of commensal, parasitic, or symbiotic relationships. 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: Anomia adamas, Anomia alectus, Anomia fidenas, Anomia hamillus, Anomia lampe, Anomia laqueata, Anomia larbas, Anomia limatula, Anomia pacilus, Anomia simplex, Anomia subcostata, Anomia tenuis, Calyptraea aberrans, and Placunomia claviculata.