The « Ranzani's Triton » is a famous rarity among the ranellids and one of S. Peter Dance's fifty Rare Shells (1969). Although described in 1850, it has a remarkable history of being « lost » for more than a century in literature until re-discovered by K. J. Grosch when diving in Mozambique in 1953. The remarks on Grosch's find was published by William K. Emerson and Anthony D'Attilio, who identified the species, in 1962. The angular but low shoulder and two distinct dark patches on the parietal callus together separates it from other Cymatium species without difficulty. A carnivorous and predatory gastropod, it inhabits shallow water to about -40m depth and ranges from Northern Arabian Sea to Mozambique including Southern Red Sea. It appears to be most comm.on in Somalia where vast majority of specimens originate, and is still moderately rare today as a result from the difficulty in obtaining material from the area due to piracy and political instability. The average shell length is about 160mm., but giants are known to exceed 240mm.

80mm. Thick, heavy, dull, the spire seeming shorter in mature specimens by development of large, flared aperture adjacent to wing-like varix opposite. Large, angulate protuberance on dorsal side of last whorl gives hump-backed appearance; about 7 broad, spiral ribs below protuberance. Spire whorls have strong, axial ribs crossed by finer spiral ribs. Ridgelike teeth inside the outer lip. Ivory with yellowish brown spiral bands; teeth have dark brown bars near edge of brown-and-white-barred outer lip; columella has large, chocolate-brown blotch; white inside aperture. May reach 220mm. Habitat: on intertidal rocks in muddy sand. Distribution Gulf of Oman, Masirah Island. Yemen coast in Indian Ocean.