Trench Tusk Shell, Dentalium vallicolens

Trench Tusk Shell, Dentalium vallicolens.  Shells collected off the beach of Punta Chivato, Baja California Sur, June 2025. Size: 2.5 cm (1.0 inches) x 0.3 cm (0.1 inches) and 3.5 cm (1.4 inches) x 0.25 cm (0.1 inches). Collection, photographs and identification courtesy of Colin Campbell, DVM, Punta Chivato.

Phylogeny: The Trench Tusk Shell, Dentalium vallicolens (Raymond, 1904),  is a marine scaphopod mollusk that is a member of the Dentaliidae Family of Tusk Shells, and a representative of the Scaphopods Class. The genus Dentalium is one of thirteen genera in this family, and there are seventy species in this genus. They are also known as Raymond’s Tusk Shell. Their common name comes from their deep water habitat.

Description: Trench Tusk Shells are tusk-shaped, and differ in appearance from juvenile to adult. Juveniles are more slender and curved, and more strongly sculpted than adults. The sculpting consists of six to seventeen axial riblets or fine striae. The striae may be completely absent in adults. The shell is round in cross-section.  The shells are glossy or chalky, depending on the amount of erosion. Juveniles are white in color, while adults tend toward beige or tan. Many specimens show healed fractures, possibly caused by predators. Trench Tusk Shells reach a maximum of 6.4 cm (2.5 inches) in length.

Habitat and Distribution:  Trench Tusk Shells are found on mud and silty substrates at depths between 5 m (16 feet) and 477 m (1,565 feet). They are a temperate to subtropical Eastern Pacific species that are found in all Mexican waters of the Pacific Ocean, however, their range is poorly documented that vary from the entire west coast, to only  present in the Sea of Cortez and/or only present in north of La Paz, Baja California Sur, in the Sea of Cortez.

Ecology and Behavior: Trench Tusk Shells are depositional feeders, which feed on foraminifera, mollusk larvae, other microorganisms, and detritus. They use specialized tentacles to collect their food. Their predators include crabs, moon snails, rays, and ratfish. They are gonochoric and reproduce sexually, with internal fertilization. Their engagement in any type of commensal, parasitic, or symbiotic relationship has not been formally documented. From a conservation perspective the Trench Tusk Shell has not been formally evaluated. However, they are fairly common with a relatively wide distribution and should be consider to be of Least Concern.

Synonyms:  None