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.
Phylogeny: The Pink-mouth Murex Shell, Phyllonotus erythrostomus (Swainson, 1831), is a gastropod mollusk that is a member of the Muricidae Family of Rock Shells. The genus Phyllonotus is one of one hundred ninety-eight genera in this family, and there are thirteen species in this genus. They are also known as the Bi-color Murex Shell and the Pink-throated Murex Shell and in Mexico as Busano Rosado and Caracol Rosa.
Description: The Pink-mouth Murex Shell is large, rugged and strongly constructed. They have six whorls and a low to moderately high spire. The varices are sculpted with numerous spines. They have a large aperture and a long, curved, siphon canal. The outer lip of the shell is marked with short spines. The inner lip can flare and 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. The Pink-mouth Murex can be confused with the Royal Murex Shell, Phyllonotus regius (dark brown to black inner lip).
Habitat and Distribution: Pink-mouth Murex Shells live on, and within, sand and mud substrates. They range from the intertidal zone to depths up to 26 m (65 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 north of Magdalena Bay, Baja California along the central and northwest coasts of the Baja Peninsula.
Ecology and Behavior: Pink-mouth Murex Shells are predators that feed primarily on bivalves. They are preyed upon by crabs, fish, and sea stars. They are gonochoric and reproduce sexually, through broadcast spawning, with external fertilization. The eggs are laid in protective capsules. There is no mention in the available literature of them engaging in any types of parasitic, commensal, or symbiotic relationships. They are edible and have been the target of commercial fisheries and shell collectors. Overharvesting has caused localized population declines. From a conservation perspective they have not been formally evaluated.
Synonyms: Chicoreus (Phyllonotus) erythrostomus, Chicoreus erythrostomus, Hexaplex (Muricanthus) erythrostomus, Hexaplex erythrostomus, Murex bicolor, Murex coccineus, Murex erythrostomus, Murex hippocastanum, and Murex regius.