Woodpile Cup-and-Saucer Shell, Crucibulum lignarium

Woodpile Cup-and-Saucer, Crucibulum lignarium. Shell collected off the beach of Punta Chivato, Baja California Sur, March 2025. Size: 2.4 cm (0.9 inches) x 0.8 cm (0.3 inches). Collection, photographs and identification courtesy of Colin Campbell, DVM, Punta Chivato.

Woodpile Cup-and-Saucer, Crucibulum lignarium. Shell collected off the beach of Punta Chivato, Baja California Sur, June 2025. Size: 2.6 cm (1.0 inch) x 1.6 cm (0.6 inches). Collection, photographs and identification courtesy of Colin Campbell, DVM, Punta Chivato.

Woodpile Cup-and-Saucer, Crucibulum lignarium. Shell collected off the beach at Las Barilles, Baja California Sur, May 2018. Size: 4.1 cm (1.6 inches) x 3.8 cm (1.5 inches. Collection, photograph and identification courtesy of Bob Hillis, Ivins, Utah.

Phylogeny: The Woodpile Cup-and-Saucer Shell, Crucibulum lignarium (Broderip, 1834), is a gastropod mollusk that is a member of the Calyptraeidae Family of Cup-and-Saucer and Slipper Limpet Shells. The Crucibulum Genus is one of eleven genera in the Calyptraeidae Family, and there are nineteen species in the Crucibulum Genus. The species name lignarium comes from the Latin words for “place of wood.”

Description: Woodpile Cup-and-Saucer Shells have variable profiles ranging from circular to trigonal. The variations follow the shape of the surface to which they are attached. The shell is high in profile. The apex is curved and set forward. These shells are sculpted by fine radial riblets and coarser, concentric, growth ridges. The inside cup is well developed. The shell, including the inside cup, is brown, gray, or white. Some individuals display brown radiating lines. Woodpile Cup-and-Saucer Shells reach a maximum of 4.6 cm (1.8 inches) in length and 4.3 cm (1.7 inches) in height.

Habitat and Distribution: Woodpile Cup-and-Saucers are found attached to rocks, stones, and other shells, especially gastropods. They live in the intertidal zone, and at depths up to 150 m (500 feet). They 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 the west coast of the Baja Peninsula and from north of Bahía de Los Ángeles, Baja California in the Sea of Cortez. Some sources state that this species is also found in the Indian Ocean, which gives it a very big, discontinuous range.

Ecology and Behavior: Woodpile Cup-and-Saucers are suspension feeders that feed primarily on plankton, which they capture with mucus nets created by their gills. They are gonochoric and reproduce sexually, through broadcast spawning. Their engagement in any type of commensal, parasitic, or symbiotic relationship has not been formally documented. From a conservation perspective the Woodpile Cup-and-Saucer has not been formally evaluated. However, they are fairly common with a relatively wide distribution and should be consider to be of Least Concern.

 Synonyms: Calyptraea lignaria