Walker’s Turrid Shell, Knefastia walkeri
Walker’s Turrid Shell, Knefastia walkeri. Shell collected off the beach of Punta Chivato, Baja California Sur, June 2025. Size: 4.0 cm (1.6 inches) x 2.2 cm (0.9 inches). Collection, photographs and identification courtesy of Colin Campbell, DVM, Punta Chivato.
Phylogeny: Walker’s Turrid Shell, Knefastia walkeri (S.S. Berry, 1958), is a gastropod mollusk that is a member of the Pseudomelatomidae Family of Turrid Shells. The Knefastia Genus is one of fifty-four genera in the Pseudomelatomidae Family, and there are ten species in Knefastia Genus. They are known in Mexico as Turrido de Walker.
Description: Walker’s Turrid Shells are fusiform (spindle-shaped) with a spire that is about twice as long as the body whorl. They consist of around eight whorls. They are sculpted with several narrow, but strong, axial ribs, and numerous spiral cords. The aperture is elongate. The anterior siphon canal is long and open, and the posterior siphon notch is pronounced. These shells are banded in various shades of brown. The periostracum is yellowish-brown and shiny. Walker’s Turrid Shells reach a maximum of 6.7 cm (2.6 inches) in length).
Habitat and Distribution: Walker’s Turrid Shells are found on mud and sand substrates. at depths between 18 m (59 feet) and 102 m (335 feet). Despite being a deeper water shell, dead specimens are found washed up on the beach. Walker’s Turrid Shells are a subtropical to tropical Eastern Pacific species and are ENDEMIC to Mexican waters with a limited range being found from Bahía de Los Ángeles, Baja California, in the Sea of Cortez, to Isla Isabela, Nayarit along the central coast of the mainland.
Ecology and Behavior: Walker’s Turrid Shells are a poorly studied and understood species. There is very limited documentation of their diet, predation, reproduction or ecosystem interactions. Other species of the Pseudomelatomidae Family are predators that feed primarily on polychaete worms. Turrid shells are similar to cone shells being venomous predators that utilize their uniquely designed radula as a harpoon to capture and then envenomate their prey. The venom paralyzes the prey animal. Turrid shells are prey for other gastropods, crabs, fish, and sea stars. Walker’s Turrid Shells 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 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.