Cyclops Cup-and-Saucer Shell, Crucibulum cyclopium

Cyclops Cup-and-Saucer Shell, Crucibulum cyclopium. Shell collected in the greater Los Cabos area, Baja Califonria Sur, July 2019. Size 8.6 cm (3.4 inches) x 7.7 cm (3.0 inches). Collection, photograph and identification courtesy of Bob Hillis, Ivins, Utah.

Phylogeny: The Cyclops Cup-and-Saucer, Crucibulum cyclopium (Berry, 1969), is a gastropod mollusk that is one of the largest members of the Calyptraeidae Family of Cup-and-Saucer and Slipper Limpets. The genus Crucibulum is on of eleven genera within this family, and there are nineteen species in this genus.

Description: Cyclops Cup-and-Saucer shells vary significantly, with some specimens displaying strong radial ridges that extend to the margins and others are that are smoother, with a more rounded profile. Often these shells are overgrown. The exterior of the shell is brown. The interior may be brown, orange or white. The septum (inside cup) is white in color, large in stature and attached only at the apex and it has ridge marks on the right side. Cyclops Cup-and-Saucer Shells reach a maximum of 9.5 cm (3.7 inches) in diameter.

Habitat and Distribution: Cyclops Cup and Saucers are found on and under rocks. They live in the intertidal zone, and to depths up to 8 m (25 feet). They are a subtropical to tropical Eastern Pacific species. In Mexican waters they range from Magdalena Bay, Baja California Sur to Guatemala. In the Gulf of California they are limited to the extreme southern portions.

Ecology and Behavior: Cyclops Cup and Saucers 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 filter plankton from the water with their gills or  depositional feeders that eat detritus.  They are protandrous hermaphrodites, meaning they change sex from male to female during their lives. They reproduce sexually, with internal fertilization. The eggs are brooded in sacs, under the shell. 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 consider to be of Least Concern.

Synonyms: None