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.

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 shells vary significantly with some specimens displaying strong radial ridges that extend to the margins and others 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 has ridge marks on the right side. Cyclops Cup-and-Saucer Shells reach a maximum of 9.5 cm (3.7 inches) in diameter.

Cyclops Cup and Saucers are found on and under rocks, in the intertidal zone to depths up to 8 m (25 feet). They range from Magdalena Bay, Baja California Sur to Costa Rica, including the Cocos Islands. In the Sea of Cortez they are limited to the extreme southern portions.