Pink-mouth Murex Shell, Phyllonotus erythrostomus

Pink-mouth Murex Shell, Phyllonotus erythrostomus. Shell provided by the commercial fishermen of the greater Los Cabos area, Baja, California Sur, June 2013. Size: 11.6 cm (4.6 inches) x 7.6 cm (3.0 inches).

Pink-mouth Murex Shell, Phyllonotus erythrostomus. Shell collected off the beach at Punta Chivato, Baja California Sur, February 2022. Size: 12.7 cm (5.0 inches) x 9.1 cm (3.6 inches) x 5.7 cm (2.3 inches). Photographs and Identifications courtesy of Colin Campbell, DVM, Punta Chivato, Baja California Sur.

The Pink-mouth Murex,  Phyllonotus erythrostomus (Swainson, 1831), is a gastropod mollusk that is a member of the Muricidae Family of Rock Shells, that is also known as the Bi-color Murex and the Pink-throated Murex and in Mexico as busano rosado and caracol rosa. The shell is rugged and strongly constructed and has six whorls, a low to moderately high spire, a curved and long siphon canal, varices have numerous spines and a large aperture. The outer lip of the shell is marked with short spines; the inner lip can be very wide. The exterior of the shell is a dull white; the interior is a beautiful porcelaneous pink, though some individuals display very little pink. Pink-mouth Murex Shells reach a maximum of 15.3 cm (6.0 inches) in length and 11.0 cm (4.3 inches) in height.

Pink-mouth Murexes live on and within sand and mud in the intertidal zone to depths up to 26 m (65 feet). They are found from Magdalena Bay, Baja California southward along the southwest coast of Baja, throughout the Sea of Cortez, and south to Peru.

The Pink-mouth Murex can be confused with the Royal Murex Shell, Phyllonotus regius (dark brown to black inner lip).

Synonyms include Chicoreus erythrostomus, Hexaplex erythrostomus, Murex bicolor, Murex erythrostomus, Murex coccineus, Murex hippocastanum, and Murex regius.