Peruvian Conch Shell, Lobatus peruvianus

Peruvian Conch Shell, Lobatus peruvianus. Shell courtesy of the commercial fishermen of the greater Los Cabos area, Baja California Sur, March 2008. Size: 16.5 cm (6.5 inches) x 9.5 cm (3.7 inches).

Phylogeny: The Peruvian Conch  Shell, Lobatus peruvianus (Swainson, 1823), is a gastropod mollusk that is a member of the Strombidae Family of True Conch Shells.  The genus Lobatus is one of thirty-one genera in this family, and there are two species in this genus. They are also known as the Cock’s Comb Conch Shell and in Mexico as Cobo Cresta De Gallo.

Description: Adult Peruvian Conch Shells have a large body whorl and a low spire. The aperture is long and flaring. In mature specimens the outer lip forms a “wing”. There is a series of folds on the upper portion of the columella and inside the outer lip. The shell’s exterior is sculpted with low revolving ridges, knobs along the shoulder, and, sometimes, a band of knobs around the body whorl. The exterior of the shell is brown or tan in color and some are variegated with white. The interior may be brownish-orange, bright orange or pink. These shells are covered with a thick dark brown periostracum. Juveniles of this species look very similar to cone shells. As they mature the shell thickens and the outer lip of the aperture begins to flare. Peruvian Conch Shells reach a maximum of 21.5 cm (8.5 inches) in length and 12.4 cm (4.9 inches) in height.

Habitat and Distribution: Peruvian Conch Shells are sand dwellers found in the intertidal zone, and to depths up to 40 m (130 feet). They are a subtropical to tropical Eastern Pacific species that are found in all Mexican waters of the Pacific Ocean with the exceptions that that are absent from north of Todos Santos, Baja California Sur along the coast of Baja and south of Puerto Libertad, Sonora in the Sea of Cortez.

Ecology and Behavior:  Peruvian Conch Shells are grazers that feed primarily on algae. They are gonochoric and reproduce sexually, with internal fertilization. They are known to host parasitic coccidians and trematodes.  There is no mention in the available literature of them engaging in any types of 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: Strombus peruvianus.