Speckled Cerith Shell, Cerithium maculosum

Speckled Cerith Shell, Cerithium maculosum. Shell collected off the beach at Punta Chivato, Baja California Sur, April 2022. Size: 4.4 cm (1.7 inches) x 1.7 cm (0.7 inches). Collection, photographs and identification courtesy of Colin Campbell, DVM, Punta Chivato, Baja California Sur.

Speckled Cerith Shell, Cerithium maculosum. Shell collected off the beach of Punta Chivato, Baja California Sur, June 2025. Size: 5.3 cm (2.1 inches) x 2.3 cm (0.9 inches). Collection, photographs and identification courtesy of Colin Campbell, DVM, Punta Chivato.

Speckled Cerith Shell, Cerithium maculosum. Shell collected off the beach at Punta Chivato, Baja California Sur, April 2022. Size: 5.3 cm (2.1 inches) x 2.0 cm (0.8 inches). Collection, photographs and identification courtesy of Colin Campbell, DVM, Punta Chivato, Baja California Sur.

Phylogeny: The Speckled Cerith Shell, Cerithium maculosum (Keiner, 1841), is a gastropod mollusk that is a member of the Cerithiidae Family of Cerith Shells. The genus Cerithium is one of forty-seven genera in this family, and there are one hundred fifty-two species in this genus. They are also known as the Common Cerith Shell and in Mexico as Cerithium Maculado or Pada Común. The name Cerithium is derived from the Greek word for “horn.”

Description: Speckled Cerith Shells are strongly built and consist of eight to nine whorls. They have a series of nodules or knobs along the shoulders, which spiral down from the apex. The shell is white to grayish, with numerous reddish-brown to dark brown specks or blotches. The aperture is white. Speckled Cerith Shells reach a maximum of 5.5 cm (2.2 inches) in length and 2.1 cm (0.8 inches) in height.

Habitat and Distribution: Speckled Ceriths reside on sand and muddy-sand substrates in the intertidal zone. They are a subtropical to tropical Eastern Pacific species that are found in all Mexican waters of the Pacific Ocean with the exception that they are absent from north of Magdalena Bay, Baja California Sur, along the central and northwest coasts of the Baja Peninsula.

Ecology and Behavior: Speckled Ceriths are opportunistic grazers that feed primarily on micro algae and detritus. They are gonochoric. The males place packets of sperm (spermatophores) on the females which the females utilize when they are ready to lay their eggs. The eggs are laid in gelatinous string-like masses. Their engagement in any type of commensal, parasitic, or symbiotic relationship has not been formulated. The Red-leg Hermit Crab, Calcinus californiensis, uses their empty shells for housing. 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: Cerithium alboliratum.