The Mighty Queen Helmet

Cassis madagascariensis is one of the largest species of mollusks living in the shallow, clean waters of the tropical western Atlantic Ocean, including Florida and the Gulf of Mexico. This spectacular mollusk, which can reach more than 40 cm (about 16 inches) in length, is a member of the family Cassidae of helmet and bonnet snails.

Cassis madagascariensis, feeding. Lake Worth Lagoon, Florida. Photo: Ariane Dimitris.

As shown in the photo above, helmet snails feed on sea urchins and sea biscuits such as the Long-spined Sea Biscuit (Plagiobrissus grandis). During feeding, Queen Helmets grab prey with the foot and use a saliva that contains sulfuric acid, which makes it easier for the snail to drill a hole through the sea-urchin’s calcium carbonate carapace. In addition, other secretions affect the nervous system of their prey, making it easier for the helmet to complete its meal.

Cassis madagascariensis, juvenile shell. Photo: James F. Kelly.

The second photo shows a juvenile shell measuring about 3 cm (1.2 inches) collected on Captiva Island, Florida. And make sure you check out a brief clip presented by yours truly here.