Black Murex Shell, Muricanthus nigritus: The Black Murex is a beautiful medium-large solid shell that is white with a black coloration on its body and spinous varices.
The young shells are pure white and progressively become more clouded with black as they increase in size. They have a high spire and a long canal.
They are found on shallow water reefs and the intertidal zone up to 75 feet in the water column and reach a maximum of 16.5 cm (6.5 inches).
They prey on clams, chipping at the edges of the valves in order to insert the proboscis and suck out all of the rich juices.
The range of this species is believed to be limited to the Sea of Cortez with larger populations found in the northern gulf. However, this collection was made along the west coast of Baja California, 50 miles north of Cabo San Lucas. The shells are sold commercially by shell collectors commanding high prices due to their beauty and rarity.
The Black Murex is a member of the Muricidae Family, a very large family, found worldwide, with approximately 100 genera and more than 700 species. The shells vary in size from one-fourth inch to ten inches high. The shell may be elongated and broadly ovate to almost round. Some have long spines, others strong axial ribs, and some species are smooth. All have a stout, horny, oval operculum.
Murexes live on rocks or reefs and are carnivores, feeding on other gastropods as well as bivalves, barnacles, worms, coral, and other invertebrates. They attack their prey by boring holes utilizing the radula and a gland in the foot that secretes various fluids to help in the boring action. The sexes are separate. The female lays the fertilized eggs in horny capsules, fastening them to rocks or hard objects singly or in clusters.