Conidae | |
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A group of shells of various species of cone snails | |
Scientific classification | |
Domain: | Eukaryota |
Kingdom: | Animalia |
Phylum: | Mollusca |
Class: | Gastropoda |
Subclass: | Caenogastropoda |
Order: | Neogastropoda |
Superfamily: | Conoidea |
Family: | Conidae Fleming, 1822 [1] |
Subfamilies and genera | |
See text | |
Synonyms | |
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Conidae, with the current common name of "cone snails", is a taxonomic family (previously subfamily) of predatory sea snails, marine gastropod molluscs in the superfamily Conoidea.
The 2014 classification of the superfamily Conoidea groups only cone snails in the family Conidae. Some previous classifications grouped the cone snails in a subfamily, Coninae.
As of March 2015 Conidae contained over 800 recognized species, varying widely in size from lengths of 1.3 cm to 21.6 cm. Working in 18th-century Europe, Carl Linnaeus knew of only 30 species that are still considered valid.
The snails within this family are sophisticated predatory animals. [2] They hunt and immobilize prey using a modified radular tooth along with a venom gland containing neurotoxins; the tooth is launched out of the snail's mouth in a harpoon-like action.
Because all cone snails are venomous and capable of "stinging" humans, live ones should be handled with great care or preferably not at all.
In the Journal of Molluscan Studies, in 2014, Puillandre, Duda, Meyer, Olivera & Bouchet presented a new classification for the old genus Conus . Using 329 species, the authors carried out molecular phylogenetic analyses. The results suggested that the authors should place all living cone snails in a single family, Conidae, containing the following genera:
The authors grouped 85% of all known cone snail species under Conus. They recognized 57 subgenera within Conus, and 11 subgenera within the genus Conasprella. [3]
Prior to 1993, the family Conidae contained only Conus species. In 1993 significant taxonomic changes were proposed by Taylor, et al.,: [4] the family Conidae was redefined as several subfamilies. The subfamilies included many subfamilies that had previously been classified in the family Turridae, and the Conus species were moved to the subfamily Coninae.
In further taxonomic changes that took place in 2009 and 2011, based upon molecular phylogeny (see below), the subfamilies that were previously in the family Turridae were elevated to the status of families in their own right. This left the family Conidae once again containing only those species that were traditionally placed in that family: the cone snail species.
According to Taylor, et al. (1993), [4] and the taxonomy of the Gastropoda by Bouchet & Rocroi, 2005, [5] this family consisted of seven subfamilies.
In 2009 John K. Tucker and Manuel J. Tenorio proposed a classification system for the cone shells and their allies (which resorb their inner walls during growth) was based upon a cladistical analysis of anatomical characters including the radular tooth, the morphology (i.e., shell characters), as well as an analysis of prior molecular phylogeny studies, all of which were used to construct phylogenetic trees. [6] In their phylogeny, Tucker and Tenorio noted the close relationship of the cone species within the various clades, corresponding to their proposed families and genera; this also corresponded to the results of prior molecular studies by Puillandre et al. and others. [7] [8] [9] [10] [11] [12] [13] This 2009 proposed classification system also outlined the taxonomy for the other clades of Conoidean gastropods (that do not resorb their inner walls), also based upon morphological, anatomical, and molecular studies, and removes the turrid snails (which are a distinct large and diverse group) from the cone snails, and creates a number of new families. [6] Tucker and Tenorio’s proposed classification system for the cone shells and their allies (and the other clades of Conoidean gastropods ) is shown in Tucker & Tenorio cone snail taxonomy 2009.
In 2011 Bouchet et al. proposed a new classification in which several subfamilies were raised to the rank of family: [14]
The classification by Bouchet et al. (2011) [14] was based on mitochondrial DNA and nuclear DNA testing, and built on the prior work by J.K. Tucker & M.J. Tenorio (2009), but did not include fossil taxa. [6] [14]
Molecular phylogeny, particularly with the advent of nuclear DNA testing in addition to the mDNA testing (testing in the Conidae initially began by Christopher Meyer and Alan Kohn [15] ), is continuing on the Conidae. [7] [8] [9] [10] [11] [12] [13] [16] [17] [18] [19] [20] [21] [22]
This is a list of what were recognized extant genera within Conidae as per J.K. Tucker & M.J. Tenorio (2009), and Bouchet et al. (2011): [6] [14] However, all these genera have become synonyms of subgenera within the genus Conus as per the revision of the taxonomy of the Conidae in 2015 [3]
Following Taylor et al., from 1993 to 2011, the family Conidae was defined as including not only the cone snails, but also a large number of other genera which are commonly known as "turrids". However, as a result of molecular phylogeny studies in 2011, many of those genera were moved back to the Turridae, or were placed in new "turrid" families within the superfamily Conoidea. The following list of genera that used to be included in Conidae is retained as a historical reference:
Species in the family Conidae are found in the tropical and subtropical seas of the world, in four biogeographic regions, including: the Indo-Pacific (with 60% of all species), the Tropical Eastern Pacific, the Western Tropical Atlantic, and the Eastern Tropical Atlantic, plus 10 species in the warm temperate Agulhas bioregion on the southern coast of South Africa. Fewer than one percent of fossil species have been found in more than one of the above regions. [23]
The oldest known fossil of Conidae is from the lower Eocene, about 55 million years ago. Analysis of nucleotide sequences indicate that all living species of Conidae belong to one of two clades that diverged about 33 million years ago. One clade includes most of the species in the eastern Pacific and western Atlantic regions, which were connected by the Central American Seaway until the emergence of the Isthmus of Panama less than three million years ago. The other clade includes most of the species in the eastern Atlantic and Indo-Pacific regions, which were connected by the Neo-Tethys Sea until 21 to 24 million years ago. [23]
Most cone snails appear to reproduce sexually, with separate sexes and internal fertilization. varying numbers of eggs in egg capsules laid in substrate by cone snails. hatchlings are of two types, the veligers (larvae that swim freely) and veliconcha (baby snail). [24]
There are approximately 30 records of humans killed by cone snails. Human victims suffer little pain, because the venom contains an analgesic component. Some species reportedly can kill a human in under five minutes, thus the name "cigarette snail" as supposedly one only has time to smoke a cigarette before dying. Cone snails can sting through a wetsuit with their harpoon-like radular tooth, which resembles a transparent needle. [25]
Normally, cone snails (and many species in the superfamily Conoidea) use their venom to immobilize prey before engulfing it. The venom consists of a mixture of peptides, called conopeptides. The venom is typically made up of 10 to 30 amino acids, but in some species as many as 60. The venom of each cone snail species may contain as many as 200 pharmacologically active components. It is estimated that more than 50,000 conopeptides can be found, because every species of cone snail is thought to produce its own specific venom.
Cone-snail venom has come to interest biotechnologists and pharmacists because of its potential medicinal properties. Production of synthetic conopeptides has started, using solid-phase peptide synthesis.
A component of the venom of Conus magus , ω-conotoxin, is now marketed as the analgesic ziconotide, which is used as a last resort in chronic and severe pain. Conopeptides are also being looked at as anti-epileptic agents and to help stop nerve-cell death after a stroke or head injury. Conopeptides also have potential in helping against spasms due to spinal cord injuries, and may be helpful in diagnosing and treating small cell carcinomas in the lung.
The biotechnology surrounding cone snails and their venom has promise for medical breakthroughs; with more than 50,000 conopeptides to study, the possibilities are numerous. [26]
Cone snails, or cones, are highly venomous sea snails of the family Conidae.
Jaspidiconus is a subgenus of sea snails, marine gastropod mollusks in the genus Conasprella, family Conidae, the cone snails and their allies.
Conasprella is a genus of sea snails, marine gastropod mollusks in the family Conidae, the cone snails and their allies. This genus was formerly treated by some experts as a member of the family Conilithidae and as an "alternative representation" of this group of species.
Dalliconus is a subgenus of sea snails, marine gastropod mollusks in the genus Conasprella, family Conidae, the cone snails and their allies.
Darioconus is a subgenus of sea snails, marine gastropod mollusks in the genus Conus, family Conidae, the cone snails and their allies.
Dauciconus is a subgenus of sea snails, marine gastropod mollusks in the genus Conus, family Conidae, the cone snails and their allies.
Dendroconus is a subgenus of sea snails, marine gastropod mollusks in the genus Conus, family Conidae, the cone snails and their allies.
The taxonomy of the cone snails and their allies as proposed by John K. Tucker and Manuel J. Tenorio in 2009 was a biological classification system for a large group of predatory sea snails. This system was an attempt to make taxonomic sense of the large and diverse group which contains the family Conidae, the cone snails. The authors proposed extensive changes to the family Conidae in contrast to the way the group was treated in the taxonomy of the Gastropoda by Bouchet & Rocroi, 2005. Bouchet and Rocroi included in the family Conidae several other groups of toxoglossan snails which had previously been placed in the Turridae.
Endemoconus is subgenus of sea snails, marine gastropod mollusks in the genus Conasprella, family Conidae, the cone snails and their allies.
Conilithidae is a proposed taxonomic family of small to medium-sized sea snails, specifically cone snails, marine gastropod mollusks in the superfamily Conoidea, the cone snails and their allies.
Fusiconus is a subgenus of sea snails, marine gastropod mollusks in the genus Conasprella, family Conidae, the cone snails and their allies.
Gradiconus is a synonym of a subgenus of sea snails, marine gastropod mollusks in the genus Conus, family Conidae, the cone snails and their allies. T
Harmoniconus is a subgenus of sea snails, marine gastropod mollusks in the family Conidae, the cone snails and their allies.
Hermes is a subgenus of sea snails, marine gastropod mollusks in the family Conidae, the cone snails and their allies.
Ketyconus is a synonym of the subgenus Conus (Floraconus)Iredale, 1930 represented as ConusLinnaeus, 1758. These are sea snails, marine gastropod mollusks in the family Conidae, the cone snails and their allies.
Kohniconus is a subgenus of sea snails, marine gastropod mollusks in the genus Conasprella, family Conilithidae, the cone snails and their allies.
Lamniconus is a subgenus of sea snails, marine gastropod mollusks in the family Conidae, the cone snails and their allies.
Leptoconus is a subgenus of sea snails, marine gastropod mollusks in the genus Conus, family Conidae, the cone snails and their allies.
Perplexiconus has become a synonym of Conasprella (Ximeniconus) Emerson & Old, 1962, a subgenus of sea snails, marine gastropod mollusks in the family Conidae, the cone snails and their allies.
Rhizoconus is a subgenus of sea snails, marine gastropod mollusks in the genus Conus, family Conidae, the cone snails and their allies.