Cortez Oyster Shell, Crassostrea corteziensis

Cortez Oyster Shell, Crassostrea corteziensis.  Shell collected from within the tidal pools of El Tule, Km17, Baja California Sur, January 2019. Size: 11.9 cm (4.6 inches) x 6.4 cm (2.5 inches).

The Cortez Oyster, Crassostrea corteziensis (Hertlein, 1951), is a bivalve mollusk that is a member of the Ostreidae Family of True Oysters. They are known in Mexico as ostra de Cortez, el ostion de placer and ostrion nativa. The shell is heavy and thick with an irregular and somewhat comma shaped profile with the left valve being more concave than the right. The exterior of the shell surface is rough. The exterior of the shell is cream or beige in color, with brownish blotches and the interior is white or cream, with purple tinges. The Cortez Oyster can reach a maximum of 25 cm (9.8 inches) in length and 13 cm (5.1 inches) in height.

Cortez Oysters are found on rocks in lagoons and in estuaries associated with mangrove roots in the intertidal zone to depths up to 2 m (6 feet). They range from the Midriff Islands, Baja California in the Sea of Cortez, to Cabo San Lucas, Baja California Sur, and south to Panama.

A synonym is Ostrea corteziensis.