Small-toothed Petricola Shell, Petricola denticulata
Small-toothed Petricola Shell, Petricola denticulata. Shell collected off the beach at Punta Chivato, Baja California Sur, January 2026. Size: 1.9 cm (0.7 inches) x 1.2 cm (0.5 inches) x 0.6 cm (0.2 inches). Collection, photographs and identification courtesy of Colin Campbell, DVM, Punta Chivato, Baja California Sur.
Small-toothed Petricola Shell, Petricola denticulata. Shell collected off the beach at Punta Chivato, Baja California Sur, January 2026. Size: 2.1 cm (0.8 inches) x 1.1 cm (0.4 inches) x 1.1 cm (0.4 inches). Collection, photographs and identification courtesy of Colin Campbell, DVM, Punta Chivato, Baja California Sur.
Phylogeny: The Small-toothed Petricola Shell, Petricola denticulata (G. B. Sowerby I, 1834), is a bivalve mollusk of the Veneridae Family of Venus Clams and the Petricolinae Subfamily. The Petricola Genus is one of eight genera in the Petricolinae Subfamily, and there are twenty-seven species in the Petricola Gnus. The genus name Petricola comes from the Latin words meaning “rock dweller”. This refers to these shells boring into rock to make a place to live. The species name denticulata comes from the Latin word meaning “small-toothed”. These shells are also called Rock Boring Clams. Until recently this genus was part of the Petricolidae Family, which has been declared not to be valid as it is superseded by the Veneridae Family.
Description: Small-toothed Petricola Shells have an elongate ovate to quadrate outline and an inflated profile. These shells are moderately thick to thick in construction. The anterior end is short and sharply rounded to truncate (appearing chopped off). The posterior is broadly to sharply rounded. The ventral margin is rounded. The beaks are low and the interior hinge is strong. Small-toothed Petricola Shells are sculpted with commarginal lamellae and around 50 strong radial ribs. The exterior of these shells is whitish to tan in color. The interior is white with purple to purplish-brown blotches posteriorly. In some specimens the entire interior is purple to purplish-brown. Small-toothed Petricola Shells reach a maximum of 4.2 cm (1.6 inches) in length.
Habitat and Distribution: Small-toothed Petricola Shells burrow into soft rocks. They live in the intertidal zone, and to depths of 22 m (72 feet). Small-toothed Petricola Shells are a subtropical to tropical Eastern Pacific species. They are found in all Mexican waters of the Pacific Ocean with the exception that they are absent from north of Bahía Santa Maria, along the central and northwest coasts of the Baja Peninsula.
Natural History: Small-toothed Petricola Shells are a poorly researched and documented species. They are infaunal suspension feeders, which feed on plankton and suspended organic matter. Their predators are not well documented. They are thought to be prey for fish, crabs, shorebirds and gastropods. Small-toothed Petricola Shells are gonochoric and reproduce sexually, through broadcast spawning. Their engagement in any type of commensal, parasitic, or mutualistic relationship has not been formally documented. From a conservation perspective Small-toothed Petricola Shells have not been formally evaluated.
Synonyms: Petricola (Petricolirus) denticulata, Petricola denticulata var. abbreviata, Petricola ventricosa, and Venerupis peruviana.