Broderip’s Thistle Trophon Shell, Acanthotrophon carduus

Broderip’s Thistle Trophon Shell, Acanthotrophon carduus. Size: 2.0 cm (0.8 inches) x 1.1 cm (0.4 inches). Shell courtesy of the commercial fishermen of the greater Los Cabos area, Baja California Sur, March 2018.

Broderip’s Thistle Trophon, Acanthotrophon carduus (Broderip, 1833), is a gastropod mollusk that is a member of the Muricidae Family of Rocks. The shell consists of seven whorls with a diamond shaped profile. Sculpting consists of nodes and spines along the tops of the whorls; more worn shells will have only spines near the aperture. The spire length is very similar to the body whorl length and the aperture is oval in shape and the inside of the outer lip is marked by a series of ridges. The siphon canal is about as long as the aperture and is open.

The exterior of the shell is scaly in texture and white in color with some specimens have brown blotches or the tips of the nodes are tipped in brown; the interior is white. Broderip’s Thistle Triton Shells reach a maximum of 2.8 cm (1.1 inches) in length and 1.5 cm (0.6 inches) in height.

Broderip’s Thistle Tritons are found attached to rocks and are found at depths between 12 m (40 feet) and 100 m (330 feet). They range from Mulegé, Baja California Sur, in the Sea of Cortez, to Peru, including the Galapagos Islands.

Synonyms include Murex carduus and Trophon carduus.