Ambiguous Murex Shell, Muricanthus ambiguus

 

Ambiguous Murex Shell, Muricanthus ambiguus. Shell collected from the beach of Bahía Concepción, Baja California Sur, October 2018. Size: 7.5 cm (3.0 inches) x 4.5 cm (1.8 inches).

Phylogeny: The Ambiguous Murex, Muricanthus ambiguus (Reeve, 1845), is a gastropod mollusk that is a member of the Muricidae Family of Rock Shells. The genus Muricanthus is one of one hundred and ninety-eight genera in this family, and there are five species in this genus. This species is known in Mexico as Busano Ambiguo.

Description: Ambiguous Murex shells are globose in shape with six whorls, a fairly low spire and a siphon that is mostly closed. They have numerous, often open, spines, many of which are frilled that vary from short and straight to long and curved. Ambiguous Murexes can be easily confused with the Black Murex Shell, Muracanthus nigritus, but they have more varices and shorter siphons. The exterior of the Ambiguous Murex Shell is white with brown to black stripes with the amount of striping varying between individuals; the interior is white. Ambiguous Murex Shells reach a maximum of 18.6 cm (7.3 inches) in length and 11.2 cm (4.4 inches) in height.

Habitat and Distribution: Ambiguous Murexes are found on rocks in the intertidal zone, and to depths up to 26 m (85 feet). They are a tropical Eastern Pacific species. They are found in the Gulf of California from Bahía Concepción to the Cabo San Lucas, Baja California Sur, and south, along the mainland coast  to Guatemala. They have not been documented from the West Coast of the Baja Peninsula.

Ecology and Behavior: Ambiguous Murexes are predators that feed primarily on bivalves. 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. From a conservation perspective they have not been formally evaluated however they are fairly common with a relatively wide distribution and should be consider to be of Least Concern.

Synonyms: Murex ambiguus, Hexaplex ambiguus, and Hexaplex (muricanthus) ambiguus.