Pacific Spiny Oyster Shell, Spondylus crassisquama

Pacific Spiny Oyster Shell, Spondylus crassisquama. Shell provided by the commercial fishermen of the greater Los Cabos area, March 2014. Size: 8.3 cm (3.3 inches) x 8.3 cm (3.3 inches). Identification courtesy of Bob Hillis, Ivins, Utah.

The Pacific Spiny Oyster, Spondylus crassisquama (Lamarck, 1819), is a bivalve mollusk that is a member of the Spondylidae Family of Spiny Oysters. They are also known as a Thorny Oyster and in Mexico as ostra espinosa. They are a close relative of the American Spiny Oyster, Spondylus americanus, of the Gulf of Mexico. The shell is heavy and usually decorated with long curving spines. The left valve is more convex than the right valve which is cemented to the substrate. The exterior of these shells vary in color from white to orange to red in color; the interior is white with a red border. The Pacific Spiny Oyster reach a maximum of 15.6 cm (6.19 inches) in length and 15.6 cm (7.9 inches) in height.

Pacific Spiny Oysters are found on vertical surfaces at depths between 10 m (35 feet) and 91 m (300 feet). They range from Scammon’s Lagoon, Baja California south to Ecuador and are found in the Sea of Cortez from Bahia Willard, Baja California south to Cabo San Lucas, Baja California Sur.

Synonyms include Spondylus basilicus, Spondylus crassiformatus, Spondylus dubius, Spondylus pictorum and Spondylus princeps.