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).

The Ambiguous Murex, Muricanthus ambiguus (Reeve, 1845), is a gastropod mollusk that is a member of the Muricidae Family of Rocks, that are known in Mexico as busano ambiguo. They 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 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.

Ambiguous Murexes are found on rocks in the intertidal zone to depths up to 26 m (85 feet). They are found in the Sea of Cortez from Bahía Concepción to the Cabo San Lucas, Baja California Sur, and south to Panama. They have not been documented from the West Coast of Baja.

Synonyms include Murex ambiguus, Murex melanoleucus, Muricanthus ambiguus, and Muricanthus callidinus.