Radish Murex Shell, Muricanthus radix
Radish Murex, Muricanthus radix. Shell collected off the beach of Punta Chivato, Baja California Sur, December 2021. Size: 11.4 cm (4.5 inches) x 8.7 cm (3.4 inches). Collection, photographs and identification courtesy of Colin Campbell, DVM, Punta Chivato.
Radish Murex, Muricanthus radix. Shell collected off the beach of Punta Chivato, Baja California Sur, December 2021. Size: 13.4 cm (5.3 inches) x 9.2 cm (3.6 inches). Collection, photographs and identification courtesy of Colin Campbell, DVM, Punta Chivato.
Phylogeny: The Radish Murex, Muricanthus radix (Gmelin, 1791), is a gastropod mollusk in the Muricidae Family of Rock Shells and the Muricinae Subfamily. The Muricanthus Genus is one of nineteen genera in the Muricinae Subfamily, and there are four species in the Muricanthus Ggenus. This species has been moved through a few genera in recent history and many sources are still classify it under the Hexaplex or Murex genus. The genus name Muricanthus comes from a combination of Latin and Greek and means “spined murex”. The species name radix comes from the Latin word for “root”, as in a root vegetable, such as a radish or beet. This species is also commonly known as the Radix Murex and the Root Murex. In Mexico this species is called Busano Pulludo.
Description: The Radish Murex Shell is noted for demonstrating “a high degree of polymorphism”, meaning that they vary in appearance. In general, these shells are solid and pear-shaped. The body whorl is large and the spire is fairly low. Eight to fourteen varices run the length of the shell, each marked with black spines. The spines tend to be open and “flowery” compared to similar shells. The aperture is large and the siphon canal is shorter than similar species in the region. The inside margin of the outer aperture lip has a tooth-like projection (labral tooth). Some sources state that this species is easily distinguished from the Black Murex Shell, Muricanthus nigritus, by the shorter spire and siphon canal. Other sources say the short spines around the mid-body whorl on the Black Murex separate it from the Radish Murex. Looking at online images of the Radish Murex will show that the lines of distinction are blurred. Initially the Ambiguous Murex, Black Murex, and Radish Murex were considered to be a part of a species complex. The Ambiguous Murex was then became a synonym of the Radish Murex and now no longer a valid species. To confidently assert to differences between these species, based on morphology, is difficult. Radish Murexes reach a maximum of 10 cm (3.9 inches) in length. Any specimen much longer than this is more likely to be a Black Murex.
Habitat and Distribution: Radish Murex Shells live on rock, gravel, mud, and sand bottoms. They are generally found from depths of 3 m (10 feet) and 40 m (131 feet). They are a subtropical to tropical tropical Eastern Pacific that are found in all Mexican waters of the Pacific Ocean with the exception that they are absent from north of Puerto Libertad, Sonora, in the Sea of Cortez and from the west coast of the Baja Peninsula.
Ecology and Behavior: Radish 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. Radish Murexes are known to host multiple species of epibionts, including algae, gastropods, bivalves, and brittle stars. This is because they are sometimes the only hard surface in a sandy environment. From a conservation perspective the Radish Murex has not been formally evaluated. However, they are fairly common with a relatively wide distribution and should be considered to be of Least Concern.
Synonyms: Hexaplex (Muricanthus) ambiguus, Hexaplex (Muricanthus) radix, Hexaplex ambiguus, Hexaplex radix, Murex ambiguus, Murex radix, and Muricanthus ambiguus.