Tumen’s Venus Clam Shell, Chione tumens

Tumen’s Venus Clam Shell, Chione tumens, Juvenile. Shell collected off the beach of Punta Chivato, Baja California Sur, June 2025. Size: 2.1 cm (0.8 inches) x 2.3 cm (0.9 inches) x 0.7 cm (0.3 inches). Collection, photographs and identification courtesy of Colin Campbell, DVM, Punta Chivato.

Tumen’s Venus Clam Shell, Chione tumens. Shell collected from within the estuary of the Magdalena Bay complex, Baja California Sur, October 2018. Size: 2.3 cm (0.9 inches) x 2.0 cm (0.8 inches).

Tumen’s Venus Clam Shell, Chione tumens. Shell collected off the beach of Punta Chivato, Baja California Sur, June 2025. Size: 3.2 cm (1.3 inches) x 3.6 cm (1.4 inches) x 1.3 cm (0.5 inches). Collection, photographs and identification courtesy of Colin Campbell, DVM, Punta Chivato.

Tumen’s Venus Clam Shell, Chione tumens. Shell collected off the beach of Punta Chivato, Baja California Sur, June 2025. Size: 3.3 cm (1.3 inches) x 3.5 cm (1.4 inches) x 2.3 cm (0.9 inches). Collection, photographs and identification courtesy of Colin Campbell, DVM, Punta Chivato.

Tumen’s Venus Clam Shell, Chione tumens. Shell collected off the beach of Punta Chivato, Baja California Sur, June 2025. Size: 4.0 cm (1.6 inches) x 4.3 cm (1.7 inches) x 1.6 cm (0.6 inches). Collection, photographs and identification courtesy of Colin Campbell, DVM, Punta Chivato.

Phylogeny: Tumen’s Venus Clam Shell, Chione tumens (Verrill, 1870), is a bivalve mollusk that is a member of the Veneridae Family of Venus Clam Shells. The genus Chione is one of one hundred seven genera in this family, and there are eleven species in this genus. They are also known as the Wedding Cake Venus Clam Shell and in Mexico as Almeja de Tumen.

Description: Tumen’s Venus Clam Shell is stout and thick, with a trigonal outline. They are equivalve (both values equal in size) and inflated. They are sculpted with 6-9 rounded commarginal undulations. The exterior of the shell may be light brown, yellowish or white, with dark brown spots and/or radiating bands intermixed with narrow angular lines. The interior is white, often with purple blush. Tumen’s Venus Clam Shells reach a maximum of 4.7 cm (1.9 inches) in length and 4.0 cm (1.6 inches) in height.

Habitat and Distribution: Tumen’s Venus Clams are found in sand and mud substrates that reside intertidally, and  to depths up to 20 m (65 feet). They are a subtropical to tropical Eastern Pacific species that are ENDEMIC to Mexico, where they 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 north coasts of the Baja Peninsula and south of Parque Nacional Huatulco, Oaxaca, along the coast of the mainland.

Ecology and Behavior: Tumen’s Venus Clams are suspension feeders that feed primarily on phytoplankton and suspended organic matter. They are prey for shorebirds, gastropods, and sea stars. They are gonochoric and reproduce sexually, through broadcast spawning. Their engagement in any type of commensal, parasitic, or symbiotic relationship has not been formally documented. 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: None