Caenogastropoda
Encyclopedia
Caenogastropoda is a taxonomic clade
Clade
A clade is a group consisting of a species and all its descendants. In the terms of biological systematics, a clade is a single "branch" on the "tree of life". The idea that such a "natural group" of organisms should be grouped together and given a taxonomic name is central to biological...

 of a large diverse group of mostly 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...

 gastropods.

Caenogastropoda contains a majority of the families of shell
Mollusc shell
The mollusc shell is typically a calcareous exoskeleton which encloses, supports and protects the soft parts of an animal in the phylum Mollusca, which includes snails, clams, tusk shells, and several other classes...

ed marine molluscs including such families as the periwinkles, cowries, wentletrap
Wentletrap
Wentletraps are small, often white, very high-spired, predatory or ectoparasitic sea snails, marine gastropod mollusks, in the family Epitoniidae.The word wentletrap originated in Dutch , and it means spiral staircase...

s, moon snails, and cone snail
Cone snail
Conidae is a taxonomic family of minute to quite large sea snails, marine gastropod molluscs in the superfamily Conoidea.The snails within this family are sophisticated predatory animals...

s.

About 60% of all living gastropods belong to Caenogastropoda.

Biology

The Caenogastropoda exhibit torsion
Torsion (gastropod)
Torsion is an anatomical event which takes place during the very early part of the life of snails and slugs of all kinds. In other words, torsion is a gastropod synapomorphy which occurs in all gastropods during larval development. Torsion is the rotation of the visceral mass, mantle and shell 180˚...

 and thus are included in what was previously been called the Streptoneura (meaning twisted nerves), also known as Prosobranchia
Prosobranchia
Not to be confused with the bivalve order Protobranchia.Prosobranchia was a large taxonomic subclass of sea snails, land snails and freshwater snails. This taxon of gastropods dates back to the 1920s...

 (meaning gills forward). Specifically, they are characterized by having only a single auricle in the heart
Heart
The heart is a myogenic muscular organ found in all animals with a circulatory system , that is responsible for pumping blood throughout the blood vessels by repeated, rhythmic contractions...

 and a single pair a gill leaflets, and are equivalent to the Monotocardia or Pectinobranchia of older authors.

Taxonomy

Caenogastropoda was first established by Leslie Reginald Cox in 1960 as a superorder but now sometimes it is retained as a clade
Clade
A clade is a group consisting of a species and all its descendants. In the terms of biological systematics, a clade is a single "branch" on the "tree of life". The idea that such a "natural group" of organisms should be grouped together and given a taxonomic name is central to biological...

. This group combines the older taxa Mesogastropoda
Mesogastropoda
Mesogastropoda was for many years a traditional taxonomic group of snails, an order. The order was composed mostly of sea snails, but it also included some land snails and freshwater snails, all of which were prosobranch gastropod mollusks....

 and Stenoglossa from classification by Johannes Thiele
Johannes Thiele
Johannes Thiele, full name Karl Hermann Johannes Thiele was a German zoologist specialized in malacology. His Handbuch der systematischen Weichtierkunde is a standard work...

 and is equivalent to the Monotocardia as defined by Mörch
Otto Andreas Lowson Mörch
Otto Andreas Lowson Mörch was a biologist, specifically a malacologist. He lived in Sweden, in Denmark, and in France.- Taxa described :Bibliography and taxa described by Otto Andreas Lowson Mörch include:...

 in 1865, as revised.

Caenogastropoda can be divided into two major groups based on the anatomy of the radula
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...

:
  • Taenioglossa (from taenio meaning band) which are the older Mesogastropoda
    Mesogastropoda
    Mesogastropoda was for many years a traditional taxonomic group of snails, an order. The order was composed mostly of sea snails, but it also included some land snails and freshwater snails, all of which were prosobranch gastropod mollusks....

     in which there are typically seven teeth in each radular row.
  • Stenoglossa (from steno meaning narrow), the Neogastropoda
    Neogastropoda
    Neogastropoda is an unranked taxonomic clade of sea snails, marine gastropod mollusks. For many years prior to 2005 Neogastropoda was an order.- Description :...

    , in which there are only 1-3 teeth per row.

1997 taxonomy

Ponder & Lindberg, 1997
Taxonomy of the Gastropoda (Ponder & Lindberg, 1997)
The taxonomy of the Gastropoda, as revised by Winston Ponder and David R. Lindberg in 1997, is an older taxonomy of the class Gastropoda, the class of molluscs consisting of all snails and slugs...

 and others since (e.g. Vega et al., 2006; Harzhauser, 2004; and Pina, 2002.) show Caenogastropoda as a superorder, following the sense of Cox, 1960. More recently Bouchet & Rocroi, 2005
Taxonomy of the Gastropoda (Bouchet & Rocroi, 2005)
The taxonomy of the Gastropoda as it was revised by Philippe Bouchet and Jean-Pierre Rocroi is currently the most up-to-date overall system for classifying gastropod mollusks...

 revised Caenogastropoda as a clade, leaving taxonomic rank for later.

2005 taxonomy

The following classification was laid out in the taxonomy of Bouchet & Rocroi (2005)
Taxonomy of the Gastropoda (Bouchet & Rocroi, 2005)
The taxonomy of the Gastropoda as it was revised by Philippe Bouchet and Jean-Pierre Rocroi is currently the most up-to-date overall system for classifying gastropod mollusks...

:
  • Caenogastropoda of uncertain systematic position
  • an informal group Architaenioglossa
    Architaenioglossa
    Architaenioglossa is a taxonomic group of snails which have gills and often an operculum. They are primarily land and freshwater gastropod mollusks within the clade Caenogastropoda....

  • clade Sorbeoconcha
    Sorbeoconcha
    Sorbeoconcha is a taxonomic clade of snails, i.e. gastropods, mainly marine species with gills and opercula, within the clade Caenogastropoda.The taxon Sorbeoconcha was named by Winston Ponder and David R. Lindberg in 1997.-1997 taxonomy:...

  • clade Hypsogastropoda
    Hypsogastropoda
    According to the Taxonomy of the Gastropoda Hypsogastropoda is a clade of parasitic marine gastropods within the clade Caenogastropoda....


2006 taxonomy

Colgan et al. (2006) provided further insight into the phylogeny of Caenogastropoda.
The source of this article is wikipedia, the free encyclopedia.  The text of this article is licensed under the GFDL.
 
x
OK