''Conus geographus'', popularly called the geography cone, geographer cone, or geographic cone, is a

species A species () is often defined as the largest group of organisms in which any two individuals of the appropriate sexes or mating types can produce fertile offspring, typically by sexual reproduction. It is the basic unit of Taxonomy (biology), ...

predatory Predation is a biological interaction in which one organism, the predator, kills and eats another organism, its prey. It is one of a family of common feeding behaviours that includes parasitism and micropredation (which usually do not kill ...

cone snail Cone snails, or cones, are highly venomous sea snails that constitute the family Conidae. ''Conidae'' is a taxonomic family (previously subfamily) of predatory marine gastropod molluscs in the superfamily Conoidea. The 2014 classification of ...

. It lives in reefs of the tropical Indo-Pacific, and hunts small fish. While all cone snails hunt and kill prey using

venom Venom or zootoxin is a type of toxin produced by an animal that is actively delivered through a wound by means of a bite, sting, or similar action. The toxin is delivered through a specially evolved ''venom apparatus'', such as fangs or a sti ...

, the venom of ''Conus geographus'' is potent enough to kill humans.WoRMS (2010). Conus geographus Linnaeus, 1758. Accessed through: World Register of Marine Species at http://www.marinespecies.org/aphia.php?p=taxdetails&id=215499 on 2011-07-24 The variety ''Conus geographus'' var. ''rosea'' G. B. Sowerby I, 1833 is a synonym of '' Conus eldredi'' Morrison, 1955. This species is the type species of : * ''Gastridium'' Modeer, 1793 * ''Rollus'' Montfort, 1810 * ''Utriculus'' Schumacher, 1817

Shell description

''C. geographus'' has a broad, thin shell, cylindrically inflated. Geography cones grow to about in length. The size of an adult shell varies between . The ground color of the shell is pink or violaceous white, occasionally reddish. It has a mottled appearance, clouded and coarsely reticulated with chestnut or chocolate, usually forming two very irregular bands. This intricate brown-and-white pattern is highly prized by shell collectors. The geography cone has a wide, violaceous white or pink

aperture In optics, the aperture of an optical system (including a system consisting of a single lens) is the hole or opening that primarily limits light propagated through the system. More specifically, the entrance pupil as the front side image o ...

and numerous shoulder ridges or spines. The shell is covered with thread-like revolving striae, usually nearly obsolete except at the base. The flattened

spire A spire is a tall, slender, pointed structure on top of a roof of a building or tower, especially at the summit of church steeples. A spire may have a square, circular, or polygonal plan, with a roughly conical or pyramidal shape. Spire ...

is striated and coronated. In comparison with other species, the shell has a noticeably wider and convex mid-body, with a flattened

. Its walls are also noticeably thinner and lighter compared to other cone shells of similar length and size. File:Cone géographique.png, Apertural view File:Conusgeographus2.jpg, Abapertural view File:Cone géographiqueFace.png, Apical view

Distribution

Geography cones are common. They occur in the

Red Sea The Red Sea is a sea inlet of the Indian Ocean, lying between Africa and Asia. Its connection to the ocean is in the south, through the Bab-el-Mandeb Strait and the Gulf of Aden. To its north lie the Sinai Peninsula, the Gulf of Aqaba, and th ...

, in the Indian Ocean off Chagos,

Réunion Réunion (; ; ; known as before 1848) is an island in the Indian Ocean that is an overseas departments and regions of France, overseas department and region of France. Part of the Mascarene Islands, it is located approximately east of the isl ...

Madagascar Madagascar, officially the Republic of Madagascar, is an island country that includes the island of Madagascar and numerous smaller peripheral islands. Lying off the southeastern coast of Africa, it is the world's List of islands by area, f ...

Mauritius Mauritius, officially the Republic of Mauritius, is an island country in the Indian Ocean, about off the southeastern coast of East Africa, east of Madagascar. It includes the main island (also called Mauritius), as well as Rodrigues, Ag ...

Mozambique Mozambique, officially the Republic of Mozambique, is a country located in Southeast Africa bordered by the Indian Ocean to the east, Tanzania to the north, Malawi and Zambia to the northwest, Zimbabwe to the west, and Eswatini and South Afr ...

and

Tanzania Tanzania, officially the United Republic of Tanzania, is a country in East Africa within the African Great Lakes region. It is bordered by Uganda to the northwest; Kenya to the northeast; the Indian Ocean to the east; Mozambique and Malawi to t ...

. They are indigenous to the reefs of the

Indo-Pacific The Indo-Pacific is a vast biogeographic region of Earth. In a narrow sense, sometimes known as the Indo-West Pacific or Indo-Pacific Asia, it comprises the tropical waters of the Indian Ocean, the western and central Pacific Ocean, and the ...

region, except for Hawaii, and off Australia (the

Northern Territory The Northern Territory (abbreviated as NT; known formally as the Northern Territory of Australia and informally as the Territory) is an states and territories of Australia, Australian internal territory in the central and central-northern regi ...

Queensland Queensland ( , commonly abbreviated as Qld) is a States and territories of Australia, state in northeastern Australia, and is the second-largest and third-most populous state in Australia. It is bordered by the Northern Territory, South Austr ...

Western Australia Western Australia (WA) is the westernmost state of Australia. It is bounded by the Indian Ocean to the north and west, the Southern Ocean to the south, the Northern Territory to the north-east, and South Australia to the south-east. Western Aust ...

Ecology

''C. geographus'' is a

piscivore A piscivore () is a carnivorous animal that primarily eats fish. Fish were the diet of early tetrapod evolution (via water-bound amphibians during the Devonian period); insectivory came next; then in time, the more terrestrially adapted repti ...

that dwells in sediment of shallow

reef A reef is a ridge or shoal of rock, coral, or similar relatively stable material lying beneath the surface of a natural body of water. Many reefs result from natural, abiotic component, abiotic (non-living) processes such as deposition (geol ...

s, preying on small fish. Like the other

s, it fires a harpoon-like, venom-tipped modified tooth into its prey; the harpoon is attached to the body by a

proboscis A proboscis () is an elongated appendage from the head of an animal, either a vertebrate or an invertebrate. In invertebrates, the term usually refers to tubular arthropod mouthparts, mouthparts used for feeding and sucking. In vertebrates, a pr ...

, and the prey is pulled inside for ingestion.

Venom

The geography cone snail is highly dangerous; live specimens should be handled with extreme caution. ''C. geographus'' has the most toxic sting known among ''Conus'' species and there are reports for about three dozen human fatalities in 300 years. The venom has an

LD50 In toxicology, the median lethal dose, LD50 (abbreviation for "lethal dose, 50%"), LC50 (lethal concentration, 50%) or LCt50 is a toxic unit that measures the lethal dose of a given substance. The value of LD50 for a substance is the dose requ ...

toxicity in the range of 0.012-0.030 mg/kg.Conus geographus Linnaeus 1758
penelope.uchicago.edu The venom of the geography cone snail is a complex mix of hundreds of different toxins that is delivered through a toxoglossan

radula The radula (; : radulae or radulas) is an anatomical structure used by mollusks for feeding, sometimes compared to a tongue. It is a minutely toothed, chitinous ribbon, which is typically used for scraping or cutting food before the food enters ...

, a

harpoon A harpoon is a long, spear-like projectile used in fishing, whaling, sealing, and other hunting to shoot, kill, and capture large fish or marine mammals such as seals, sea cows, and whales. It impales the target and secures it with barb or ...

-like tooth propelled from an extendable

. There is no

antivenom Antivenom, also known as antivenin, venom antiserum, and antivenom immunoglobulin, is a specific treatment for envenomation. It is composed of antibodies and used to treat certain venomous bites and stings. Antivenoms are recommended only if ...

for a cone snail sting, and treatment consists of keeping victims alive until the toxins wear off. The geography cone is also known colloquially as the "cigarette snail", a gallows humor exaggeration implying that, when stung by this creature, the victim will have only enough time to smoke a cigarette before dying. In reality, even the most venomous cone snails take about one to five hours to kill a healthy human, though medical care must still be prompt as, without it, death is almost certain. Among the compounds found in cone snail venom are proteins which, when isolated, have great potential as pain-killing drugs. Research shows that certain component proteins of the venom target specific human pain receptors and can be up to 10,000 times more potent than morphine without morphine's addictive properties and side-effects.

Conotoxin A conotoxin is one of a group of neurotoxic peptides isolated from the venom of the marine cone snail, genus '' Conus''. Conotoxins, which are peptides consisting of 10 to 30 amino acid residues, typically have one or more disulfide bonds. C ...

-G is a toxin derived from the

of ''C. geographus''. Only 15-20 of the venom's 100-200 toxic peptides are used for feeding. It is believed that the other compounds are defensive, and that the venom is mainly used for defense.

Insulin

Recent research has revealed that ''C. geographus'' uses a form of

insulin Insulin (, from Latin ''insula'', 'island') is a peptide hormone produced by beta cells of the pancreatic islets encoded in humans by the insulin (''INS)'' gene. It is the main Anabolism, anabolic hormone of the body. It regulates the metabol ...

as a means of stunning its prey. This insulin is distinct from its own (with shorter chains) and appears to be a stripped down version of those insulins found in fish. Once this venom passes through a fish's gills, the fish experiences hypoglycaemic shock, essentially stunning it and allowing for ingestion by the snail. This poison mixture has been referred to as ''nirvana cabal''. Along with the tulip cone snail '' C. tulipa'', no other species of any known lifeform is known to have used its own biological insulin as a weapon.

References

This article incorporates CC-BY-3.0 text from the reference.

Linnaeus, C. (1758). Systema Naturae per regna tria naturae, secundum classes, ordines, genera, species, cum characteribus, differentiis, synonymis, locis. Editio decima, reformata. Laurentius Salvius: Holmiae. ii, 824 pp
* Dufo, M.H. 1840. ''Observations sur les Mollusques marins, terrestres et fluviatiles des iles Séchelles et des Amirantes''. Annales des Sciences Naturelles, Paris 2 14, Zoologie: 45-80 (extrait), 166-221(suite) * Reeve, L.A. 1843. ''Monograph of the genus Conus''. pls 1-39 in Reeve, L.A. (ed.). Conchologica Iconica. London : L. Reeve & Co. Vol. 1. * Hedley, C. 1899. ''The Mollusca of Funafuti. Part 1. Gastropoda.'' Memoirs of the Australian Museum 3(7): 395-488, 49 text figs * Schepman, M.M. 1913. ''Toxoglossa.'' 384-396 in Weber, M. & de Beaufort, L.F. (eds). The Prosobranchia, Pulmonata and Opisthobranchia Tectibranchiata, Tribe Bullomorpha, of the Siboga Expedition. Monograph 49. Siboga Expeditie 32(2) * Allan, J.K. 1950. ''Australian Shells: with related animals living in the sea, in freshwater and on the land''. Melbourne : Georgian House xix, 470 pp., 45 pls, 112 text figs. * Satyamurti, S.T. 1952. ''Mollusca of Krusadai Is. I. Amphineura and Gastropoda''. Bulletin of the Madras Government Museum, Natural History ns 1(no. 2, pt 6): 267 pp., 34 pls * Gillett, K. & McNeill, F. 1959. ''The Great Barrier Reef and Adjacent Isles: a comprehensive survey for visitor, naturalist and photographer''. Sydney : Coral Press 209 pp. * McMichael, D.F. 1960. ''Shells of the Australian Sea-Shore''. Brisbane : Jacaranda Press 127 pp., 287 figs. * Rippingale, O.H. & McMichael, D.F. 1961. ''Queensland and Great Barrier Reef Shells''. Brisbane : Jacaranda Press 210 pp. * Wilson, B.R. & Gillett, K. 1971. ''Australian Shells: illustrating and describing 600 species of marine gastropods found in Australian waters''. Sydney : Reed Books 168 pp. * Hinton, A. 1972. ''Shells of New Guinea and the Central Indo-Pacific''. Milton : Jacaranda Press xviii 94 pp. * Salvat, B. & Rives, C. 1975. ''Coquillages de Polynésie.'' Tahiti : Papéete Les editions du pacifique, pp. 1–391. * Cernohorsky, W.O. 1978. ''Tropical Pacific Marine Shells.'' Sydney : Pacific Publications 352 pp., 68 pls. * Wilson, B. 1994. ''Australian Marine Shells. Prosobranch Gastropods''. Kallaroo, WA : Odyssey Publishing Vol. 2 370 pp. * Röckel, D., Korn, W. & Kohn, A.J. 1995. ''Manual of the Living Conidae. Volume 1: Indo-Pacific Region''. Wiesbaden : Hemmen 517 pp. * Filmer R.M. (2001). ''A Catalogue of Nomenclature and Taxonomy in the Living Conidae 1758 - 1998''. Backhuys Publishers, Leiden. 388pp * Tucker J.K. (2009). ''Recent cone species database''. September 4, 2009 Edition * Tucker J.K. & Tenorio M.J. (2009) ''Systematic classification of Recent and fossil conoidean gastropods''. Hackenheim: Conchbooks. 296 pp
Puillandre N., Duda T.F., Meyer C., Olivera B.M. & Bouchet P. (2015). ''One, four or 100 genera? A new classification of the cone snails.'' Journal of Molluscan Studies. 81: 1-23

Gallery

File:Conus geographus 1.jpg, ''Conus geographus'' Linnaeus, C., 1758 File:Conus geographus 2.jpg, ''Conus geographus'' Linnaeus, C., 1758 File:Conus geographus 3.jpg, ''Conus geographus'' Linnaeus, C., 1758 File:Conus geographus 4.jpg, ''Conus geographus'' Linnaeus, C., 1758

External links

by James Grout. *
Cone Shells - Knights of the Sea
* {{DEFAULTSORT:Conus Geographus geographus Gastropods described in 1758 Taxa named by Carl Linnaeus