Unguis Turban Shell, Uvanilla unguis

Unguis Turban Shell, Uvanilla unguis. Shell courtesy of the commercial fishermen of the greater Los Cabos area, May 2011. Size: 2.7 cm (1.1 inches) x 1.8 cm (0.7 inches).

Unguis Turban Shell, Uvanilla unguis. Shell collected off the beach of Punta Chivato, Baja California Sur, March 2025. Size: 4.2 cm (1.7 inches) x 2.8 cm (1.1 inches). Collection, photographs and identification courtesy of Colin Campbell, DVM, Punta Chivato.

Phylogeny: The Unguis Turban Shell, Uvanilla unguis (W. Wood, 1828), is a gastropod mollusk that is a member of the Turbinidae Family of Turban Shells. The genus Uvanilla is one of eighteen genera in this family, and there are four species in this genus. The name unguis comes from the Latin word for claw, referring to the shape of the basal spines.

Description: Unguis Turban Shells are wide and cone shaped and they are the only top shell in the region that have a series of blunt spines projecting from the perimeter of the base. The shell consists of five or six sloping whorls. The exterior is sculpted strong radiating ribs and fine spiral cords. The base has a semi-circle of fine concentric cords, which give way to  nacre. These shells are gray to light brown in color. Unguis Turban Shells reach a maximum of 6.2 cm (2.4 inches) in diameter.

Habitat and Distribution: Unguis Turbans are found clinging to rocks in the intertidal zone, and at depths up to 81 m (265 feet). 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 the west coast of the Baja Peninsula and from north of Bahía San Carlos, Sonora, in the Sea of Cortez.

Ecology and Behavior: Unguis Turbans are herbivorous grazers that feed primarily on algae and detritus. They are gonochoric and reproduce sexually, with external fertilization. The eggs are laid as a gelatinous mass. Their engagement in any type of commensal, parasitic, or symbiotic relationship has not been formally documented. From a conservation perspective the Unguis Turban Shell has not been formally evaluated. However, they are fairly common with a relatively wide distribution and should be considered to be of Least Concern.

Synonyms: Astraea unguis, Trochus amictus, Trochus chemnitzii, Trochus unguis, and Turbo digitatus.