Lewis’ Moon Shell, Neverita lewisii

Lewis’ Moon Shell, Neverita lewisii, Size Progression. Proceeding counterclockwise – 9.8 cm (3.9 inches) x 8.3 cm (3.3 inches);  5.9 cm 2.3 inches) x 4.5 cm (1.8 inches); 2.9 cm (1.1 inches) x 2.3 cm (0.9 inches); 2.3 cm (0.9 inches) x 1.9 cm (0.7 inches). Shell provided by the commercial fishermen of the greater Los Cabos area, Baja California Sur, August 2008.

Lewis’ Moon Shell, Neverita lewisii. Shell provided by the commercial fishermen of the greater Los Cabos area, Baja California Sur, August 2008.Size: 5.9 cm (2.3 inches) x 4.5 cm (1.8 inches).

Lewis’ Moon, Neverita lewisii. Shell provided by the commercial fishermen of the greater Los Cabos area, Baja California Sur, August 2008. Size: 9.8 cm (3.9 inches) x 8.3 cm (3.3 inches).

Phylogeny: The Lewis’ Moon Shell, Neverita lewisii (Gould, 1847), is a gastropod mollusk that is a member of the Naticidae Family of Moon Shells. The genus Neverita is one of thirty-eight genera in this family, and there are eight species in this genus. They are also known as the Western Moon Snail and in Mexico as Caracol Luna de Lewis. The family name Naticidae comes from the Latin for “little buttocks” or “small rounded form”.

Description: Lewis’ Moon Shells are large, solid, shells that consist of four to five whorls, with the body whorl making up almost the entire shell mass. The exterior is mostly smooth, but sometimes marked by gray growth lines. The exterior of the shell is yellowish gray to tan or brown in color. The interior is porcelaneous and white, often with brown blotching. The operculum is made of a thick horn-like material.  Lewis’ Moon Shells reach a maximum of 16.6 cm (6.5 inches) in length and 14.0 cm (5.5 inches) in height.

Habitat and Distribution: Lewis’ Moon Shells reside on and within sand and mud substrates from the intertidal zone to depths up to 50 m (165 feet). They are a temperate to subtropical Eastern Pacific species that are found in Mexican waters of the Pacific Ocean along the central and northwest coasts of the Baja peninsula from the California border south to Magdalena Bay, Baja California Sur. They are not found in the Sea of Cortez.

Ecology and Behavior: Lewis’ Moon Shells are predators that feed primarily on bivalves. They are gonochoric and reproduce sexually,  with internal fertilization. The eggs are laid in a “sand collar”. Lewis’ Moon Shells are known to host endoparasitic trematodes. There is no mention in the available literature of them engaging in any types of  commensal or symbiotic relationships. Lewis’ Moon Shells are edible, but not highly in demand. 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:  Euspira lewisii, Lunatia lewisii, Natica lewisii, Polinices lewisi, and Polinices lewisii.