8th June 2017: World Oceans Day

In honour of the World Oceans Day, we thought we’d revisit an article looking at the importance of a fascinating animal in our collections. (This article was originally published in PuLSe in June 2015.)

Carl Linnaeus described this species as Conus geographus (the geography cone) in 1758. It was one of 700 molluscan species to be published in the tenth edition of his Systema Naturae, a book that radically changed taxonomy and nomenclature. In the 12th edition of that work (1767) the number of described molluscs increased by over a hundred, and a further 28 were described in the “Regni Animalis appendix” of his Mantissa Plantarum (1771). The Linnean Society of London holds 1,564 lots of Linnaean mollusca, all of which have been digitised and are available to view online. 

Linnaeus based the description on the only thing available to him—the shell of the animal. Like many early taxonomists, he probably never saw the animal alive, solely working with the shell itself. Yet, the same animal described over 250 years ago is revolutionising science and saving lives.

C. geographus is one of 600 species of cones from the largest genus of marine animals. This group of sea snails is found worldwide in tropical and subtropical seas, with the highest diversity in the tropical Indo-West Pacific region. Cone snails are most commonly found in the sublittoral epipelagic zone, living on sandy regions or among rocks or coral reefs. They are carnivorous, highly-evolved predators, hunting prey such as marine worms, fish or other gastropods. The shells themselves have proven to be highly prized by shell collectors due to the variety of colours (brown, white or black), and the intricate and diverse patterns (dotted, zigzag or striped).

Though their slow movement might otherwise preclude successful predation, an adaptation enables cone snails to catch their prey—a harpoon-like radula (primarily made of the polysaccharide chitin) is shot from the proboscis. This radula, or modified tooth, contains the venom conotoxin, a mixture of short peptides that induces neuromuscular paralysis in its prey, which is then swallowed whole. While all cone snails have this adaptation, interestingly no two species have the same venom proteins, and C. geographus itself dispenses two venoms—one defensive and one predatory. The venom of C. geographus is potentially fatal to humans; well known as the most venomous of all known cone snail species, it is considered to be one of the most deadly animals in the world, even nicknamed the “cigarette snail”, as a victim, once stung, may only have time for one last cigarette. Envenomations by Conus geographus are extremely rare (only ca. 15 deaths have been attributed, with conviction, to cone snails in Goldfrank's Toxicologic Emergencies). Nevertheless, there is no antivenom for a cone snail sting, and treatment is limited to merely keeping victims alive until the toxins wear off.