Chelyconus
Encyclopedia
Chelyconus is a proposed genus
of sea snail
s, marine
gastropod mollusks in the family
Conidae, the cone snails
and their allies. This genus currently (November 2011) is still treated by some experts as an "alternative representation" of this group of species.
When the "alternative representations" are not used, this group of species is instead still placed in the Linnaean
genus Conus
.
(WoRMS) list. Species within the genus Chelyconus include:
The following species names are recognized as "alternate representations" (see full explanation below) in contrast to the traditional system, which uses the genus Conus
for all species in the family:
. In 2009 however, J.K. Tucker and M.J. Tenorio proposed a classification system for the over 600 recognized species
that were in the family. Their classification proposed 3 distinct families and 82 genera for the living species of cone snails. This classification was based upon shell
morphology
, radular
differences, anatomy
, physiology
, cladistics
, with comparisons to molecular (DNA) studies. Published accounts of genera within the Conidae that include the genus Chelyconus include J.K. Tucker & M.J. Tenorio (2009), and Bouchet et al. (2011).
Testing in order to try to understand the molecular phylogeny
of the Conidae was initially begun by Christopher Meyer and Alan Kohn, and is continuing, particularly with the advent of nuclear DNA testing in addition to mDNA testing.
However, in 2011, some experts still prefer to use the traditional classification, where all species are placed in Conus
within the single family Conidae: for example, according to the current November 2011 version of the World Register of Marine Species
, all species within the family Conidae are in the genus Conus
. The binomial names of species in the 82 cone snail genera listed in Tucker & Tenorio 2009 are recognized by the World Register of Marine Species
as "alternative representations." Debate within the scientific community regarding this issue continues, and additional molecular phylogeny
studies are being carried out in an attempt to clarify the issue.
Genus
In biology, a genus is a low-level taxonomic rank used in the biological classification of living and fossil organisms, which is an example of definition by genus and differentia...
of sea snail
Sea snail
Sea snail is a common name for those snails that normally live in saltwater, marine gastropod molluscs....
s, marine
Marine (ocean)
Marine is an umbrella term. As an adjective it is usually applicable to things relating to the sea or ocean, such as marine biology, marine ecology and marine geology...
gastropod mollusks in the family
Family (biology)
In biological classification, family is* a taxonomic rank. Other well-known ranks are life, domain, kingdom, phylum, class, order, genus, and species, with family fitting between order and genus. As for the other well-known ranks, there is the option of an immediately lower rank, indicated by the...
Conidae, the cone snails
Conus
Conus is a large genus of small to large predatory sea snails, marine gastropod molluscs, with the common names of cone snails, cone shells or cones. This genus is placed in the subfamily Coninae within the family Conidae. Geologically speaking, the genus is known from the Eocene to the Recent ...
and their allies. This genus currently (November 2011) is still treated by some experts as an "alternative representation" of this group of species.
When the "alternative representations" are not used, this group of species is instead still placed in the Linnaean
Linnaean taxonomy
Linnaean taxonomy can mean either of two related concepts:# the particular form of biological classification set up by Carl Linnaeus, as set forth in his Systema Naturæ and subsequent works...
genus Conus
Conus
Conus is a large genus of small to large predatory sea snails, marine gastropod molluscs, with the common names of cone snails, cone shells or cones. This genus is placed in the subfamily Coninae within the family Conidae. Geologically speaking, the genus is known from the Eocene to the Recent ...
.
Distinguishing characteristics
The Tucker & Tenorio 2009 taxonomy distinguishes Chelyconus from Conus in the following ways:- Genus Conus sensu stricto Linnaeus, 1758
-
- Shell characters (living and fossil species)
- The basic shell shape is conical to elongated conical, has a deep anal notch on the shoulder, a smooth periostracumPeriostracumThe periostracum is a thin organic coating or "skin" which is the outermost layer of the shell of many shelled animals, including mollusks and brachiopods. Among mollusks it is primarily seen in snails and clams, i.e. in bivalves and gastropods, but it is also found in cephalopods such as the...
and a small operculumOperculum (gastropod)The operculum, meaning little lid, is a corneous or calcareous anatomical structure which exists in many groups of sea snails and freshwater snails, and also in a few groups of land snails...
. The shoulder of the shell is usually nodulose and the protoconchProtoconchA protoconch is an embryonic or larval shell of some classes of molluscs, e.g., the initial chamber of an ammonite or the larval shell of a gastropod...
is usually multispiral. Markings often include the presence of tents except for black or white color variants, with the absence of spiral lines of minute tents and textile bars.
- The basic shell shape is conical to elongated conical, has a deep anal notch on the shoulder, a smooth periostracum
- Radular tooth (not known for fossil species)
- The radulaRadulaThe radula is an anatomical structure that is used by molluscs for feeding, sometimes compared rather inaccurately to a tongue. It is a minutely toothed, chitinous ribbon, which is typically used for scraping or cutting food before the food enters the esophagus...
has an elongated anterior section with serrations and a large exposed terminating cusp, a non-obvious waist, blade is either small or absent and has a short barb, and lacks a basal spur.
- The radula
- Geographical distribution
- These species are found in the Indo-PacificIndo-PacificThe Indo-Pacific is a biogeographic region of the Earth's seas, comprising the tropical waters of the Indian Ocean, the western and central Pacific Ocean, and the seas connecting the two in the general area of Indonesia...
region.
- These species are found in the Indo-Pacific
- Feeding habits
- These species eat other gastropods including cones.
- Shell characters (living and fossil species)
- Genus ChelyconusChelyconusChelyconus is a proposed genus of sea snails, marine gastropod mollusks in the family Conidae, the cone snails and their allies. This genus currently is still treated by some experts as an "alternative representation" of this group of species.When the "alternative representations" are not used,...
Mörch, 1852
-
- Shell characters (living and fossil species)
- The protoconchProtoconchA protoconch is an embryonic or larval shell of some classes of molluscs, e.g., the initial chamber of an ammonite or the larval shell of a gastropod...
is multispiral, the shell is ovate to elongated conical in shape, the spire is conical to convex, the shoulders are rounded, and the surface of the shell has minute ridges. The anterior notch may be absent to moderate in depth, and the shell has a moderate to shallow anal notch. The periostracumPeriostracumThe periostracum is a thin organic coating or "skin" which is the outermost layer of the shell of many shelled animals, including mollusks and brachiopods. Among mollusks it is primarily seen in snails and clams, i.e. in bivalves and gastropods, but it is also found in cephalopods such as the...
is smooth, and the operculum is small.
- The protoconch
- Radular tooth (not known for fossil species)
- The anterior section of the radulaRadulaThe radula is an anatomical structure that is used by molluscs for feeding, sometimes compared rather inaccurately to a tongue. It is a minutely toothed, chitinous ribbon, which is typically used for scraping or cutting food before the food enters the esophagus...
is much longer than posterior section, and the waist is not obvious. A basal spur is absent, the barb and blade are short. The accessory process is well developed and is not hooked on the distal end.
- The anterior section of the radula
- Geographical distribution
- One species is found in the Atlantic and the other occurs in the Eastern Pacific region.
- One species is found in the Atlantic and the other occurs in the Eastern Pacific region.
- Feeding habits
- These species are piscivorous (meaning that they prey on fish).
- Shell characters (living and fossil species)
Species list
This list of species is based on the information in the World Register of Marine SpeciesWorld Register of Marine Species
The World Register of Marine Species is a database that hopes to provide an authoritative and comprehensive list of names of marine organisms. The content of the registry is edited and maintained by scientific specialists on each group of organism. These taxonomists control the quality of the...
(WoRMS) list. Species within the genus Chelyconus include:
The following species names are recognized as "alternate representations" (see full explanation below) in contrast to the traditional system, which uses the genus Conus
Conus
Conus is a large genus of small to large predatory sea snails, marine gastropod molluscs, with the common names of cone snails, cone shells or cones. This genus is placed in the subfamily Coninae within the family Conidae. Geologically speaking, the genus is known from the Eocene to the Recent ...
for all species in the family:
- Chelyconus ermineus (Born, 1778) is equivalent to Conus ermineusConus ermineusConus ermineus is a species of sea snail, a marine gastropod mollusk in the family Conidae, the cone snails and their allies.Like all species within the genus Conus, these snails are predatory and venomous...
Born, 1778 - Chelyconus purpurascens (G.B. Sowerby I, 1833) is equivalent to Conus purpurascensConus purpurascensConus purpurascens is a species of sea snail, a marine gastropod mollusk in the family Conidae, the cone snails and their allies.Like all species within the genus Conus, these snails are predatory and venomous. They are capable of "stinging" humans, therefore live ones should be handled carefully...
G. B. Sowerby I, 1833
Significance of "alternative representation"
Prior to 2009, all species within the family Conidae were placed in one genus, ConusConus
Conus is a large genus of small to large predatory sea snails, marine gastropod molluscs, with the common names of cone snails, cone shells or cones. This genus is placed in the subfamily Coninae within the family Conidae. Geologically speaking, the genus is known from the Eocene to the Recent ...
. In 2009 however, J.K. Tucker and M.J. Tenorio proposed a classification system for the over 600 recognized species
Species
In biology, a species is one of the basic units of biological classification and a taxonomic rank. A species is often defined as a group of organisms capable of interbreeding and producing fertile offspring. While in many cases this definition is adequate, more precise or differing measures are...
that were in the family. Their classification proposed 3 distinct families and 82 genera for the living species of cone snails. This classification was based upon shell
Gastropod shell
The gastropod shell is a shell which is part of the body of a gastropod or snail, one kind of mollusc. The gastropod shell is an external skeleton or exoskeleton, which serves not only for muscle attachment, but also for protection from predators and from mechanical damage...
morphology
Morphology (biology)
In biology, morphology is a branch of bioscience dealing with the study of the form and structure of organisms and their specific structural features....
, radular
Radula
The radula is an anatomical structure that is used by molluscs for feeding, sometimes compared rather inaccurately to a tongue. It is a minutely toothed, chitinous ribbon, which is typically used for scraping or cutting food before the food enters the esophagus...
differences, anatomy
Anatomy
Anatomy is a branch of biology and medicine that is the consideration of the structure of living things. It is a general term that includes human anatomy, animal anatomy , and plant anatomy...
, physiology
Physiology
Physiology is the science of the function of living systems. This includes how organisms, organ systems, organs, cells, and bio-molecules carry out the chemical or physical functions that exist in a living system. The highest honor awarded in physiology is the Nobel Prize in Physiology or...
, cladistics
Cladistics
Cladistics is a method of classifying species of organisms into groups called clades, which consist of an ancestor organism and all its descendants . For example, birds, dinosaurs, crocodiles, and all descendants of their most recent common ancestor form a clade...
, with comparisons to molecular (DNA) studies. Published accounts of genera within the Conidae that include the genus Chelyconus include J.K. Tucker & M.J. Tenorio (2009), and Bouchet et al. (2011).
Testing in order to try to understand the molecular phylogeny
Molecular phylogeny
Molecular phylogenetics is the analysis of hereditary molecular differences, mainly in DNA sequences, to gain information on an organism's evolutionary relationships. The result of a molecular phylogenetic analysis is expressed in a phylogenetic tree...
of the Conidae was initially begun by Christopher Meyer and Alan Kohn, and is continuing, particularly with the advent of nuclear DNA testing in addition to mDNA testing.
However, in 2011, some experts still prefer to use the traditional classification, where all species are placed in Conus
Conus
Conus is a large genus of small to large predatory sea snails, marine gastropod molluscs, with the common names of cone snails, cone shells or cones. This genus is placed in the subfamily Coninae within the family Conidae. Geologically speaking, the genus is known from the Eocene to the Recent ...
within the single family Conidae: for example, according to the current November 2011 version of the World Register of Marine Species
World Register of Marine Species
The World Register of Marine Species is a database that hopes to provide an authoritative and comprehensive list of names of marine organisms. The content of the registry is edited and maintained by scientific specialists on each group of organism. These taxonomists control the quality of the...
, all species within the family Conidae are in the genus Conus
Conus
Conus is a large genus of small to large predatory sea snails, marine gastropod molluscs, with the common names of cone snails, cone shells or cones. This genus is placed in the subfamily Coninae within the family Conidae. Geologically speaking, the genus is known from the Eocene to the Recent ...
. The binomial names of species in the 82 cone snail genera listed in Tucker & Tenorio 2009 are recognized by the World Register of Marine Species
World Register of Marine Species
The World Register of Marine Species is a database that hopes to provide an authoritative and comprehensive list of names of marine organisms. The content of the registry is edited and maintained by scientific specialists on each group of organism. These taxonomists control the quality of the...
as "alternative representations." Debate within the scientific community regarding this issue continues, and additional molecular phylogeny
Molecular phylogeny
Molecular phylogenetics is the analysis of hereditary molecular differences, mainly in DNA sequences, to gain information on an organism's evolutionary relationships. The result of a molecular phylogenetic analysis is expressed in a phylogenetic tree...
studies are being carried out in an attempt to clarify the issue.
Further reading
- Kohn A. A. (1992). Chronological Taxonomy of Conus, 1758-1840". Smithsonian Institution Press, Washington and London.
- Monteiro A. (ed.) (2007). The Cone Collector 1: 1-28.
- Berschauer D. (2010). Technology and the Fall of the Mono-Generic Family The Cone Collector 15: pp. 51-54
- Puillandre N., Meyer C.P., Bouchet P., and Olivera B.M. (2011), Genetic divergence and geographical variation in the deep-water Conus orbignyi complex (Mollusca: Conoidea), Zoologica Scripta 40(4) 350-363.