Cone snail
Cone snails use a modified radula tooth and a venom gland to attack and paralyze their prey before engulfing it.
The tooth, which is likened to a dart or a harpoon, is barbed and can be extended some distance out from the head of the snail at the end of the proboscis.
They live on a variety of substrates, from the intertidal zone and deeper areas, to sand, rocks or coral reefs.
In other species, the topmost shell layer is a thin periostracum, a transparent yellowish or brownish membrane.
The cone snails immobilize their prey using a modified, dartlike, barbed radular tooth, made of chitin, along with a venom gland containing neurotoxins.
The researchers hypothesize that these chemicals cause the prey to be more easily harpooned, but are still uncertain as to exactly how this occurs in the wild.
[14][15] The venom of cone snails contains hundreds of different compounds, and its exact composition varies widely from one species to another.
The toxins in cone snail venom are referred to as conotoxins, and are composed of various peptides, each targeting a specific nerve channel or receptor.
[14][20] Symptoms of a more serious cone snail sting include severe, localized pain, swelling, numbness and tingling, and vomiting.
[21] The appeal of conotoxins for creating pharmaceutical drugs is the precision and speed with which the chemicals act; many of the compounds target only a particular class of receptor.
Ziconotide, a pain reliever 1,000 times as powerful as morphine, was initially isolated from the venom of the magician cone snail, Conus magus.
[23][24] Many peptides produced by the cone snails show prospects for being potent pharmaceuticals, such as AVC1, isolated from the Australian species, the Queen Victoria cone, Conus victoriae, and have been highly effective in treating postsurgical and neuropathic pain, even accelerating recovery from nerve injury.
Geography and tulip cone snails are known to secrete a type of insulin that paralyzes nearby fish by causing hypoglycaemic shock.
[27][28] Conus gloriamaris, also known as "Glory of the Seas", one of the most famous and sought-after seashells in past centuries, with only a few specimens in private collections.
In Hawaii, these natural beads were traditionally collected from the beach drift to make puka shell jewelry.
In 2009, J.K. Tucker and M.J. Tenorio proposed a classification system consisting of three distinct families and 82 genera for living species of cone snails.
This classification is based on shell morphology, radular differences, anatomy, physiology, and cladistics, with comparisons to molecular (DNA) studies.
[31][34][35][36][37][38][39][40][41][42] In 2015, in the Journal of Molluscan Studies, Puillandre, Duda, Meyer, Olivera & Bouchet presented a new classification for the old genus Conus.
The results suggested that the authors should place all cone snails in a single family, Conidae, containing four genera: Conus, Conasprella, Profundiconus and Californiconus.
