Archaeogastropoda (also known as Aspidobranchia) was 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. ...

order of

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 used in older classifications of

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 ...

s, i.e.

snail A snail is, in loose terms, a shelled gastropod. The name is most often applied to land snails, terrestrial pulmonate gastropod molluscs. However, the common name ''snail'' is also used for most of the members of the molluscan class Gastro ...

s and

slug Slug, or land slug, is a common name for any apparently shell-less terrestrial gastropod mollusc. The word ''slug'' is also often used as part of the common name of any gastropod mollusc that has no shell, a very reduced shell, or only a smal ...

s. Archeogastropoda are

marine Marine is an adjective meaning of or pertaining to the sea or ocean. Marine or marines may refer to: Ocean * Maritime (disambiguation) * Marine art * Marine biology * Marine debris * Marine habitats * Marine life * Marine pollution Military * ...

prosobranch 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). Gene ...

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, mainly

herbivore A herbivore is an animal anatomically and physiologically adapted to eating plant material, for example foliage or marine algae, for the main component of its diet. As a result of their plant diet, herbivorous animals typically have mouthpart ...

s, typically having two

gill A gill () is a respiratory organ that many aquatic organisms use to extract dissolved oxygen from water and to excrete carbon dioxide. The gills of some species, such as hermit crabs, have adapted to allow respiration on land provided they are ...

s and a double-chambered heart, with the eggs and sperm discharged directly into the water. They were traditionally regarded as a relatively primitive group. This older classification of the gastropods is based on the classification of Johannes Thiele (1925). This classification was not based on true

phylogenetic In biology, phylogenetics (; from Greek φυλή/ φῦλον [] "tribe, clan, race", and wikt:γενετικός, γενετικός [] "origin, source, birth") is the study of the evolutionary history and relationships among or within groups o ...

relationships, but on more general affinities between the groups. In the last few years, two new

cladistic Cladistics (; ) is an approach to biological classification in which organisms are categorized in groups (" clades") based on hypotheses of most recent common ancestry. The evidence for hypothesized relationships is typically shared derived char ...

taxonomies of the gastropods have been published (in 1997 and 2005). This has led to an extensive reclassification of gastropod taxa. The taxon Archaeogastropoda was found to be a

paraphyletic In taxonomy (general), taxonomy, a group is paraphyletic if it consists of the group's most recent common ancestor, last common ancestor and most of its descendants, excluding a few Monophyly, monophyletic subgroups. The group is said to be pa ...

group, and therefore unacceptable in a strictly cladistic classification. In the 1997 classification, most of the former Archaeogastropoda were included in: *subclass

Eogastropoda Eogastropoda was a previously used taxonomic category of snails or gastropods, a subclass which was erected by Ponder and Lindberg in 1997. It was one of two great divisions (subclasses) of the class Gastropoda, the snails. The other subclass of ...

**order

Patellogastropoda The Patellogastropoda, common name true limpet Limpets are a group of aquatic snails that exhibit a conical shell shape (patelliform) and a strong, muscular foot. Limpets are members of the class Gastropoda, but are polyphyletic, meaning th ...

(limpets) *subclass

Orthogastropoda Orthogastropoda was a major taxonomic grouping of snails and slugs, an extremely large subclass within the huge class Gastropoda according to the older taxonomy of the Gastropoda (Ponder & Lindberg, 1997). This taxon is no longer used accordin ...

**Superorder

Vetigastropoda Vetigastropoda is a major Taxonomy (biology), taxonomic group of sea snails, marine (ocean), marine gastropod mollusc, mollusks that form a very ancient lineage (evolution), lineage. Taxonomically the Vetigastropoda are sometimes treated as an O ...

Salvini-Plawen, 1989 **Superorder Neritaemorphi Koken, 1896 (with the order Neritopsina Cox & Knight, 1960). A more detailed classification can be found on

Gastropoda 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. ...

Older system of classification

*Order Archaeogastropoda **Superfamily

Pleurotomariacea Pleurotomariacea is one of two names that are used for a taxonomic superfamily of sea snails that are an ancient lineage and are well represented in the fossil record. The name Pleurotomariacea is used by paleontologists, who, because they us ...

***Family Pleurotomariidae ***Family

Haliotidae ''Haliotis'', common name abalone, is the only genus in the family Haliotidae. This genus once contained six subgenera. These subgenera have become alternate representations of ''Haliotis''. The genus consists of small to very large, edible, h ...

***Family

Scissurellidae Scissurellidae, sometimes known by the common name little slit snails, are a taxonomic family of minute sea snails, marine gastropod molluscs or micromolluscs in the clade Vetigastropoda (according to the taxonomy of the Gastropoda by Bouchet & ...

**Superfamily Fissurellacea ***Family

Fissurellidae Fissurellidae, common name the keyhole limpets and slit limpets, is a taxonomic family of limpet-like sea snails, marine gastropod molluscs in the clade Vetigastropoda.Rosenberg, G. (2012). Fissurellidae. Accessed through: World Register of Marin ...

**Superfamily Patellacea ***Family

Patellidae Patellidae is a taxonomic family of sea snails or true limpets, marine gastropod molluscs in the clade Patellogastropoda. (The superfamily Patelloidea should not be confused with the similar-sounding genus of true limpets ''Patelloida'' which ...

***Family

Acmaeidae Acmaeidae is a family of sea snails, specifically true limpets, marine gastropod mollusks in the superfamily Lottioidea and the subclass Patellogastropoda (according to the taxonomy of the Gastropoda by Bouchet & Rocroi, 2005). Bouchet, P. ...

***Family

Lepetidae Lepetidae is a family of sea snails or small, deep-water true limpets, marine gastropod molluscs in the clade Patellogastropoda the true limpets. Taxonomy This family consists of the two following subfamilies (according to the taxonomy of t ...

**Superfamily Trochacea ***Family

Calliostomatidae Calliostomatidae is a family of sea snails within the superfamily Trochoidea and the clade Vetigastropoda.Gofas, S. (2013). Calliostomatidae. Accessed through: World Register of Marine Species at http://www.marinespecies.org/aphia.php?p=taxdetail ...

***Family

Trochidae The Trochidae, common name top-snails or top-shells, are a family of various sized sea snails, marine gastropod molluscs in the subclass Vetigastropoda. This family is commonly known as the top-snails because in many species the shell resembles ...

***Family Stomatellidae ***Family Cyclostrematidae ***Family

Turbinidae Turbinidae, the turban snails, are a family of small to large marine gastropod molluscs in the superfamily Trochoidea.Bouchet, P. (2014). Turbinidae Rafinesque, 1815. Accessed through: World Register of Marine Species at http://www.marinespecie ...

***Family

Phasianellidae Phasianellidae common name the "pheasant shells" or "pheasant snails" is a family of small sea snails with calcareous opercula, marine gastropod mollusks in the subclass Vetigastropoda Vetigastropoda is a major Taxonomy (biology), taxonomi ...

**Superfamily Neritacea ***Family

Neritidae Neritidae, common name the nerites, is a taxonomic family of small to medium-sized saltwater and freshwater snails which have a gill and a distinctive operculum. MolluscaBase eds. (2021). MolluscaBase. Neritininae Poey, 1852. Accessed through: ...

***Family

Helicinidae Helicinidae is a family of small tropical land snails which have an operculum. They are terrestrial operculate gastropod mollusks in the superfamily Helicinoidea. These snails are not at all closely related to the air-breathing land snails, des ...

***Family

Hydrocenidae Hydrocenidae is a taxonomic family of minute land snails or cave snails with an operculum, terrestrial gastropod mollusks or micromollusks in the clade Cycloneritimorpha. Hydrocenidae are widespread across the Palearctis and Africa, but r ...

References

External links

* Sasaki T. (1998)
"Comparative anatomy and phylogeny of the recent Archaeogastropoda (Mollusca: Gastropoda)"
''Bulletin'' 38. Tokyo. {{Taxonbar, from=Q445364 Obsolete gastropod taxa Extant Cambrian first appearances Taxa named by Johannes Thiele (zoologist)

Older system of classification

See also

References

External links