Cheilea Hoof Shell, Cheilea cepacea
Cheilea Hoof Shell, Cheilea cepacea. Shell collected off the beach of Punta Chivato, Baja California Sur, May 2025. Size: 0.8 cm (0.3 inches) x 0.7 cm (0.3 inches). Collection, photographs and identification courtesy of Colin Campbell, DVM, Punta Chivato.
Cheilea Hoof Shell, Cheilea cepacea. Shell collected off the beach of Punta Chivato, Baja California Sur, May 2025. Size: 2.8 cm (1.1 inches) x 2.8 cm (1.1 inches) x 0.9 cm (0.4 inches). Collection, photographs and identification courtesy of Colin Campbell, DVM, Punta Chivato.
Phylogeny: The Cheilea Hoof Shell, Cheilea cepacea (Broderip 1834), is a gastropod mollusk that is a member of the Hipponicidae Family of Hoof Shells. The genus Cheilea is one of eight genera in this family, and there are twenty-one species in this genus. They are also known as the False Cup and Saucer Shell and in Mexico as Concha de Casco Falso and Sombrero Chino. The name cepacea comes from the Latin word for onion, referring to this shell’s exterior’s resemblance to a sliced onion.
Description: Cheilea Hoof Shells are irregularly circular in outline, with a conical profile. The apex may be centralized or placed forward on the shell. The exterior is sculpted with low radial ridges and commarginal growth rings. The interior support is semi-circular and attached only at its base. This support is very similar to the cup found in the Calyptraeidae Family of Cup-and-Saucer Shells and Slipper Limpet Shells, and for many years this species was mistakenly placed in that family. The exterior may be shiny or chalky white. The interior is shiny white. Cheilea Hoof Shells reach a diameter of around 2.0 cm (0.75 inches).
Habitat and Distribution: Cheilea Hoof Shells are found attached to rocks and shells in the lower intertidal zone, and to a depth of 183 m (600 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.Some sources include the Philippines in the distribution though this seems extremely discontinuous and may be based on mistaken identity.
Ecology and Behavior: Cheilea Hoof 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 Hipponicidae feed primarily on organic fragments, detritus, and pieces of algae. Because they are sedentary, they use their extendable snout to reach food sources and are dependent on water movement to bring them food. They are sequential hermaphrodites, beginning life as males and transitioning into females. They reproduce sexually, through broadcast spawning. The eggs sacs are brooded under the female’s shell. Beyond their sometimes being an epibiont on other shells, 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 wide distribution and should be consider to be of Least Concern.
Synonyms: Calyptraea cepacea, Calyptraea cornea, and Calyptraea planulata.