Fluctuating Turban Shell, Turbo fluctuosus
Fluctuating Turban Shell, Turbo fluctuosus. Shell courtesy of the commercial fishermen of the greater Los Cabos area, Baja California Sur, July 2011. Size: 5.2 cm (2.0 inches) x 5.2 cm (2.0 inches).
Phylogeny: The Fluctuating Turban Shell, Turbo fluctuosus (Wood, 1828), is a gastropod mollusk that is a member of the Turbinidae Family of Turban Shells. The genus Turbo is one of eighteen genera in this family, and there are sixty-one species in this genus. They are also known as the Gulf Turban Shell, the Eastern Pacific Turban Shell, the Stoney Turban Shell, and the Wavy Turban Shell and in Mexico as Turbante del Pacifico.
Description: Fluctuating Turban Shells are sturdy and consist of five rounded whorls that have angled shoulders. The whorls are sculpted with spiral ridges, which vary from fine to very coarse and nodular. These shells are taller than they are wide. They have a large, round, smooth, aperture. The exterior of the shell is highly variable in color and may be light brown, reddish brown, greenish, or orange, with whitish and dark brown mottling. The interior is iridescent. Fluctuating Turban Shells reach a maximum of 8.6 cm (3.3 inches) of length and 8.6 cm (3.3 inches) in height.
Habitat and Distribution: Fluctuating Turban Shells are found most commonly on, or under, rocks, or over, and within, mud and sand substrates. They live in the intertidal zone, and to depths up to 40 m (130 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 Cedros Island, Baja California along the central and northwest coasts of the Baja Peninsula and south of Puerto Vallarta, Jalisco, including the Tres Marias Islands, along the central and southwest coasts of the mainland.
Ecology and Behavior: Fluctuating Turban Shells are herbivorous grazers that feed primarily on algae, including cyanobacteria and diatoms. They are simultaneous hermaphrodites (each snail possesses both male and female reproductive organs) and reproduce sexually, through broadcast spawning, with external fertilization. There is no mention in the available literature of them engaging in any types of parasitic, commensal, or symbiotic relationships. Fluctuating Turban Shells are popular in the aquarium trade, which could subject them to localized over-collecting. 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: Callopoma (Turbo) fluctuatum, Callopoma fluctuatum, Turbo (Callopoma) fluctuosus, Turbo assimilis, Turbo fluctuates, Turbo fokkesi, and Turbo tessellatus.