Pectinatum Cup-and-Saucer Shell, Crucibulum pectinatum

Pectinatum Cup-and-Saucer Shell, Crucibulum pectinatum. Shell collected off the beach of Punta Chivato, Baja California Sur, March 2025. Size: 2.3 cm (0.9 inches) x 2.2 cm (0.9 inches) x 0.6 cm (0.2 inches). Collection, photographs and identification courtesy of Colin Campbell, DVM, Punta Chivato.

Pectinatum Cup-and-Saucer Shell, Crucibulum pectinatum. Shell collected off the beach of Punta Chivato, Baja California Sur, March 2025. Size: 2.9 cm (1.1 inches) x 2.4 cm (0.9 inches) x 1.0 cm (0.4 inches). Collection, photographs and identification courtesy of Colin Campbell, DVM, Punta Chivato.

Phylogeny: The Pectinatum Cup-and-Saucer Shell, Crucibulum pectinatum (Carpenter 1856), is a gastropod mollusk in the Calyptraeidae Family of Cup-and-Saucer Shells and Slipper Limpet Shells. The genus Crucibulum is one of eleven genera in this family, and there are nineteen species in this genus. They are known in as the Picacho Shell. The specific name pectinatum means comb-like, referring to the scalloping along the shell’s margin.

Description: Pectinatum Cup-and Saucer Shells have an irregular oval outline and a pagoda-like profile. Most specimens have a steep apex, which steps down to the margin.  Strong radial ribs extend past the margin, forming an irregular scalloping along the perimeter. The internal cup is flattened on one edge. The exterior color ranges from orangish-brown to grayish brown. The interior is smooth and white, often with orange or brown staining. Pectinatum Cup-and Saucer Shells reach a maximum of 2.9 cm (1.1 inches) in length.

Habitat and Distribution: Pectinatum Cup-and Saucer Shells are found attached to rocks at depths between 14 m (46 feet) and 27 m (89 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 along the west coast of the Baja Peninsula.

Ecology and Behavior: Pectinatum Cup-and Saucer Shells are a poorly studied and understood species. There is very limited documentation of their diet, predation, reproduction or ecosystem interactions. Other species in Family Calyptraeidae are either  suspension feeders that feed primarily on plankton, which they capture with mucus nets created by their gills, or depositional feeders that eat detritus. They are gonochoric and reproduce sexually. There is no mention in the available literature of them engaging in any types of parasitic, commensal, 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:   None.