Caenogastropoda is a

taxonomic Taxonomy is the practice and science of categorization or classification. A taxonomy (or taxonomical classification) is a scheme of classification, especially a hierarchical classification, in which things are organized into groups or types. ...

clade A clade (), also known as a monophyletic group or natural group, is a group of organisms that are monophyletic – that is, composed of a common ancestor and all its lineal descendants – on a phylogenetic tree. Rather than the English term, ...

, a large diverse group which are mostly

sea snail Sea snail is a common name for slow-moving marine gastropod molluscs, usually with visible external shells, such as whelk or abalone. They share the taxonomic class Gastropoda with slugs, which are distinguished from snails primarily by the ...

s and other marine

gastropod The gastropods (), commonly known as snails and slugs, belong to a large taxonomic class of invertebrates within the phylum Mollusca called Gastropoda (). This class comprises snails and slugs from saltwater, from freshwater, and from land. T ...

mollusk Mollusca is the second-largest phylum of invertebrate animals after the Arthropoda, the members of which are known as molluscs or mollusks (). Around 85,000 extant species of molluscs are recognized. The number of fossil species is e ...

s, but also includes some

freshwater snail Freshwater snails are gastropod mollusks which live in fresh water. There are many different families. They are found throughout the world in various habitats, ranging from ephemeral pools to the largest lakes, and from small seeps and springs ...

s and some land snails. The clade is the most diverse and ecologically successful of the gastropods. Caenogastropoda contains many families of shelled marine molluscs – including the periwinkles,

cowries Cowrie or cowry () is the common name for a group of small to large sea snails, marine gastropod mollusks in the family Cypraeidae, the cowries. The term '' porcelain'' derives from the old Italian term for the cowrie shell (''porcellana' ...

wentletrap Wentletraps are small, often white, very high-spired, predatory or ectoparasitic sea snails, marine gastropod mollusks in the family Epitoniidae.Gofas, S. (2010). Epitoniidae. In: Bouchet, P.; Gofas, S.; Rosenberg, G. (2010) World Marine Mollusc ...

moon snails Naticidae, common name moon snails or necklace shells, is a family of medium to large-sized predatory sea snails, marine gastropod molluscs in the clade Littorinimorpha. The shells of the species in this family are mostly globular in shape. Nat ...

, murexes,

cone snail A cone is a three-dimensional geometric shape that tapers smoothly from a flat base (frequently, though not necessarily, circular) to a point called the apex or vertex. A cone is formed by a set of line segments, half-lines, or lines con ...

s and

turrid Turrid, plural turrids, is a common name for a very large group of predatory sea snails, marine gastropod mollusks which until recently were all classified in the family Turridae. However, recently the family was discovered to be polyphyletic ...

s – and constitutes about 60% of all living gastropods.

Biology

The Caenogastropoda exhibit

torsion Torsion may refer to: Science * Torsion (mechanics), the twisting of an object due to an applied torque * Torsion of spacetime, the field used in Einstein–Cartan theory and ** Alternatives to general relativity * Torsion angle, in chemistry Bi ...

, and thus are included in what was previously called the Streptoneura (meaning ''twisted nerves''), also known as

Prosobranchia Prosobranchia was a large taxonomic subclass of sea snails, land snails and freshwater snails. This taxon of gastropods dates back to the 1920s. It has however been proven to be polyphyletic (consisting of more than one lineage of descent). Gen ...

(meaning ''gills forward''). Specifically, they are characterized by having only a single auricle in the

heart The heart is a muscular organ in most animals. This organ pumps blood through the blood vessels of the circulatory system. The pumped blood carries oxygen and nutrients to the body, while carrying metabolic waste such as carbon dioxide t ...

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

Taxonomy

The

taxon In biology, a taxon (back-formation from ''taxonomy''; plural taxa) is a group of one or more populations of an organism or organisms seen by taxonomists to form a unit. Although neither is required, a taxon is usually known by a particular nam ...

Caenogastropoda was first established by Leslie Reginald Cox in 1960 as a superorder but now sometimes it is retained as a

. Based on optimal phylogenetic analysis, it is deemed

monophyletic In cladistics for a group of organisms, monophyly is the condition of being a clade—that is, a group of taxa composed only of a common ancestor (or more precisely an ancestral population) and all of its lineal descendants. Monophyletic gro ...

. This Caenogastropoda combines the older taxa Mesogastropoda and Stenoglossa from the classification by Johannes Thiele and is equivalent to the revised Monotocardia as defined by Mörch in 1865. Caenogastropoda can be divided into two major groups, based on the anatomy of the radula: * Taenioglossa (from ''taenio'' meaning ''band''), equivalent to the older Mesogastropoda, with typically seven teeth in each radular row. * Stenoglossa (from ''steno'' meaning ''narrow''), the

Neogastropoda Neogastropoda is an order of sea snails, both freshwater and marine gastropod molluscs. Description The available fossil record of Neogastropoda is relatively complete, and supports a widely accepted evolutionary scenario of an Early Creta ...

, with only 1–3 teeth per row.

1997 taxonomy

Ponder & Lindberg, 1997 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 revised Caenogastropoda as a clade.

2005 taxonomy

The following classification was laid out in the taxonomy of Bouchet & Rocroi (2005): * Caenogastropoda of uncertain systematic position * an informal group Architaenioglossa * clade

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. Taxonomy 1 ...

* clade Hypsogastropoda

2006 taxonomy

Colgan et al. (2006) provided further insight into the phylogeny of Caenogastropoda.

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World Register of Marine Species The World Register of Marine Species (WoRMS) is a taxonomic database that aims to provide an authoritative and comprehensive list of names of marine organisms. Content The content of the registry is edited and maintained by scientific specialist ...

Sorbeoconcha should include erithioidea + Campaniloidea + all Hypsogastropoda (i.e. the remaining Caenogastropoda) see definition in Ponder & Lindberg, 1997: 225, not only erithioidea + Campaniloideaas suggested by the indent pattern in Bouchet & Rocroi. Neotaenioglossa Haller, 1892 suggested in Ruud Bank’s draft for Fauna Europaea is not retained because it would need severe emendation to remove Pyramidellids, Cerithioids, etc. included in its original definition, and therefore would be too far from Haller's concept if it were to fit the concept of Sorbeoconcha. Although cladistically sound, the taxon Sorbeoconcha is skipped in the classification scheme because (1) ten years after its publication, the name still sounds unfamiliar to most and (2) it is not very helpful in the classification because it includes the bulk of Caenogastropoda (only keeping out small stem groups

Abyssochrysidae Abyssochrysidae is a family (biology), family of sea snails, marine (ocean), marine gastropod Mollusc, mollusks in the clade Caenogastropoda (according to the Taxonomy of the Gastropoda (Bouchet & Rocroi, 2005), taxonomy of the Gastropoda by Bouc ...

, Provannidae, and the architaenioglossate taxa). This is not final, opinions are welcome. ;Taxonomy as provided by WoRMS in 2021 WoRMS (2021). Caenogastropoda. Accessed at: http://www.marinespecies.org/aphia.php?p=taxdetails&id=224570 on 2021-07-26: * Subterclass

* Superorder Hypsogastropoda * Order Architaenioglossa * Order

Littorinimorpha Littorinimorpha is a large order of snails, gastropods, consisting primarily of sea snails (marine species), but also including some freshwater snails ( aquatic species) and land snails ( terrestrial species).Bouchet P. & Rocroi J.-P. (Ed.); Frý ...

* Order

* Order nassignedCaenogastropoda (temporary name) * Order Stenoglossa has become a synonym of

References

External links

{{Taxonbar, from=Q132979 Gastropod taxonomy Protostome unranked clades Carboniferous first appearances