Phorcus atratus

Phorcus atratus is a marine gastropod mollusk with a solid, imperforate shell that typically measures between 17 mm and 24 mm in height and 16 mm to 19 mm in diameter. The shell has a conical shape with 5 to 6 whorls, featuring eroded apical whorls and a dull cinereous or purplish-black coloration marked by spiral rows of white spots or longitudinal zigzag white stripes. The base of the shell is often tessellated or striped with white, and the aperture is oblique with a short columella that is slightly subdentate at its base. This species exhibits variability in coloration, particularly in young specimens that may be perforate. Phorcus atratus is found in various marine environments, including the Cape Verdes, Canary Islands, and European waters, extending to Senegal. It typically inhabits rocky substrates, where it can be encountered at various dive sites. Divers may observe this species on the seafloor, often blending in with its surroundings due to its cryptic coloration. Encounters with this snail can be intriguing, as its unique shell structure and patterns can be easily mistaken for other similar species. The diet of Phorcus atratus primarily consists of algae, as it is herbivorous. Breeding habits are not extensively documented in the sources, but like many gastropods, it may engage in reproductive behaviors typical of marine snails. The conservation status of this species is not evaluated in the sources.