Conidae

Current 2014 taxonomy

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 four genera: Conus, Conasprella, Profundiconus and Californiconus. 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.

Overview

Prior to 1993, the family Conidae contained only Conus species. In 1993, significant taxonomic changes were proposed by Taylor, et al.,: the family Conidae was redefined as several subfamilies. The subfamilies included many subfamilies which had previously been classified in the family Turridae, and the Conus species were moved to the subfamily Coninae.

In further taxonomic changes which took place in 2009 and 2011, based upon molecular phylogeny (see below), the subfamilies which 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 which were traditionally placed in that family: the cone snail species.

1993, Taylor et al, Bouchet & Rocroi

According to Taylor, et al. (1993) and the taxonomy of the Gastropoda by Bouchet & Rocroi, 2005, this family consisted of seven subfamilies.

2009, Tucker & Tenorio

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. 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. 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. 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.

2011, Bouchet et al.

In 2011, Bouchet et al. proposed a new classification in which several subfamilies were raised to the rank of family:

The classification by Bouchet et al. (2011) 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.

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), is continuing on the Conidae.

2009, 2011, list of genera from Tucker & Tenorio, and Bouchet et al

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): 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

1993 to 2011 list of genera

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:

Cone snail venom characteristics and biotech

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.

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.

W-conopeptide, from the species Conus magus is the basis of the analgesic drug Prialt, an approved treatment for pain said to be 1000 times as powerful as morphine and used as a last resort in specific application. 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.