California Horn Shell, Cerithideopsis californica
California Horn Shell, Cerithideopsis californica. Shell collected near shore, San Diego, CA., May 2017. Size: 3.9 cm (1.5 inches) x 1.6 cm (0.6 inches). Collection, photograph and identification courtesy of Bob Hillis, Ivins, Utah.
Phylogeny: The California Horn Shell, Cerithideopsis californica (Haldeman, 1840), is a member gastropod mollusk that is a member of the Potamididae Family of Horn Shells. The genus Cerithideopsis is one of six genera in this family, and there are ten species in this genus. They are known in Mexico as Caracol de Coño.
Description: California Horn Shells have a narrow cone-shaped profile with about ten, slightly rounded whorls and a round aperture. The exterior of the shell is sculpted by weak length-wise and spiral ridges. Most specimens will display one or more short varices. The operculum is corneous (made of horn-like material). The interior and exterior of the shells are brown in color. California Horn Shells reach a maximum of 4.4 cm (1.7 inches) in length and 1.8 cm (0.7 inches) in width.
Habitat and Distribution: California Horn Shells are found in large aggregations on sandy mud substrate in bays and estuaries. They live in the intertidal zone, and to depths up to 5 m (15 feet). They are a temperate Eastern Pacific species. In Mexican waters they are found along the west coast of the Baja Peninsula, ranging from the northern border to San Ignacio Lagoon, Baja California Sur. The California Horn Shell is very similar to the Mazatlán Horn Shell, Certhidea mazatlanica (white varices and aperture lips) that is found in the Gulf of California and south to Panama.
Ecology and Behavior: California Horn Shells are omnivorous grazers that feed primarily on algae, diatoms, and decaying organic matter. They are prey for fish, crabs, and shore birds. California Horn Shells are gonochoric and reproduce sexually, through broadcast spawning, with external fertilization. They reproduce March through October. This species has a relatively long life-span of 6-10 years. They are known to host 18 different parasitic trematode species. California Horn Shells are very tolerant of wet and dry conditions as well as extremes of salinity. From a conservation perspective they have not been formally evaluated however they are common with a relatively wide distribution and should be consider to be of Least Concern.
Synonyms: Cerithidea aguayoi, Cerithidea albonodosa, Cerithidea californica, Cerithidea mazatlanica, Cerithidea sacrata, Cerithidea valida, Cerithium (Potamis) sacratum, Cerithium aguayoi, Cerithium californicum, Cerithium fortiusculum, Cerithium sacratum, Cerithium varicosum, Potamides (Cerithidea) californica, and Potamides meta.