Gastropoda
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223566569
2008-07-04T17:28:20Z
Amog
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Reverted edits by [[Special:Contributions/122.2.105.105|122.2.105.105]] to last version by DOI bot (using [[WP:HG|Huggle]])
{{Taxobox
| name = Gastropod
| fossil_range = Late [[Cambrian]] - Recent
| image = Cypraea chinensis with partially extended mantle.jpg
| image_width = 240px
| image_caption = Marine gastropod ''Cypraea chinensis''
| regnum = [[Animal]]ia
| phylum = [[Mollusca]]
| classis = '''Gastropoda'''
| classis_authority = [[Georges Cuvier|Cuvier]], 1797
| subdivision_ranks = Subclasses
| subdivision =
[[Eogastropoda]] (True Limpets and relatives)<br>
[[Orthogastropoda]] }}
The [[class (biology)|class]] '''Gastropoda''' or the '''gastropods''', also previously known as '''gasteropods''', or '''univalves''', and more commonly known as [[snails]], are the most diversified [[class (biology)|class]] belonging to the [[phylum]] of [[mollusca|mollusk]]s, with 60,000-75,000 known living [[species]]. This class of animals is second only to [[insects]] in its number of known species.
The class Gastropoda is striking in its extraordinary diversification of [[habitat]]s. Representatives live in [[garden]]s, in [[woodland]], in [[desert]]s, and on [[mountain]]s; in small [[ditch]]es, great [[river]]s and [[lake]]s; in [[estuaries]], [[mudflat]]s, the rocky [[intertidal]], the sandy subtidal, in the [[abyssal]] depths of the [[ocean]]s, and numerous other ecological niches, including [[parasitic]] ones.
This class includes very large numbers of species of [[Marine (ocean)|marine]] snails and [[sea slug]]s, as well as freshwater snails and freshwater [[limpet]]s, and the [[Terrestrial animal|terrestrial]] (land) snails and [[slug]]s.
Although the name "snail" can be, and often is, applied to all the members of this class, very commonly the word "snail" is restricted to those species which have an external [[Gastropod shell|shell]] large enough that the soft parts can withdraw completely into it. Those gastropods without a shell, and those which have only a very reduced or internal shell, are often known as slugs.
The marine shelled species of gastropod include edible species such as [[abalone]], [[conch]]es, [[Common periwinkle|periwinkle]]s, [[whelk]]s, and numerous other sea snails which have coiled [[seashell]]s. There are also a number of [[Family (biology)|families]] of species such as all the various [[limpet]]s, where the shell is coiled only in the [[larval]] stage, and is a simple conical structure after that.
==Distribution==
The gastropods have a worldwide distribution, in the seas and oceans, in brackish water, in freshwater and on land, from the near Arctic and Antarctic zones to the tropics.
==Habitat==
The gastropods have become adapted to almost every kind of existence on earth, having colonized every medium available except the air. In habitats where there is not enough [[calcium carbonate]] to build a really solid shell, such as on some acidic soils on land, one can find various species of slugs, and also some snails which have a thin translucent shell, mostly or entirely composed of protein.
Snails such as <i>Sphincterochila boissieri</i> and <i>Trochoidea seetzenii</i> have adapted to desert conditions, others to an existence in ditches, near deepwater hydrothermal vents, the pounding surf of rocky shores, caves, and many other diverse areas.
== Description ==
[[Image:Prosobranchia male.png|left|thumb|Drawing of a male prosobranch gastropod<br>light yellow - body<br>brown - [[Gastropod shell|shell]] and [[Operculum (gastropod)|operculum]]<br>green - digestive system<br>light violet - [[gills]]<br>yellow - [[osphradium]]<br>red - heart<br>pink - <br>dark violet - <br>
1. foot<br>
2. pleural ganglion<br>
3. [[pneumostome]]<br>
4. upper [[commissura]]<br>
5. [[osphradium]]<br>
6. [[gills]]<br>
7. ? ganglion<br>
8. atrium of heart<br>
9. visceral ganglion<br>
10. [[ventricle]]<br>
11. foot<br>
12. [[Operculum (gastropod)|operculum]]<br>
13. brain<br>
14. mouth<br>
15. tentacle<br>
16. eye<br>
17. tentacle<br>
18. ?<br>
19. pedal ganglion<br>
20. lower commissura<br>
21. ?<br>
22. pallial cavity / [[Mantle (mollusc)|mantle]] cavity / respiratory cavity<br>
23. parietal ganglion<br>
24. anus<br>
25. [[hepatopancreas]]<br>
26. [[vas deferens]]<br>
27. [[rectum]]<br>
28. [[nephridium]]]]
[[Image:Snail_diagram-en.svg|right|thumb|Anatomy of a common snail]]
{{main|Gastropod shell}}
Snails are distinguished by [[Torsion (gastropod)|torsion]], a process where the visceral mass of the animal rotates 180º to one side during development, such that the anus is situated more or less above the head. (This process is unrelated to the coiling of the shell, which is a separate phenomenon.) Torsion is present in all gastropods, but the opisthobranch gastropods are secondarily de-torted. However, this "rotation hypothesis" is being challenged by the "asymmetry hypothesis" in which the gastropod mantle cavity originated from one side only of a bilateral set of mantle cavities <ref name="gastropod development">{{cite journal | author=Louise R. Page| title=Modern insights on gastropod development: Reevaluation of the evolution of a novel body plan| journal= Integrative and Comparative Biology| year=2006| volume=46| issue=2| url=http://intl-icb.oxfordjournals.org/cgi/content/full/46/2/134| pages=134–143| doi=10.1093/icb/icj018}}</ref>
Gastropods typically have a well-defined [[head (anatomy)|head]] with two or four sensory [[tentacle]]s, and a ventral foot, which gives them their name ([[Greek language|Greek]] ''gaster'', [[stomach]], and ''poda'', [[foot|feet]]). The eyes that may be present at the tip of the tentacles range from simple [[ocelli]] that cannot project an image (simply distinguishing light and dark), to more complex pit and even lens eyes <ref>{{cite book | last=Götting | first=Klaus-Jürgen | title= Lexikon der Biologie | chapter=Schnecken | editor=Becker, U., Ganter, S., Just, C. & Sauermost, R. | year=1994 | publisher=Spektrum Akademischer Verlag | location=Heidelberg | id=ISBN 3-86025-156-2}}</ref>. The larval shell of a gastropod is called a [[protoconch]].
[[Image:Zonitoides nitidus drawing.svg|right|thumb|[[Gastropod shell|The shell]] of ''[[Zonitoides nitidus]]'', a small land snail, has dextral coiling, which is typical of gastropod shells, but which is not universally found.<br>
''Upper image:'' dorsal view of the shell, showing the apex<br>
''Central image:'' lateral view showing the spire and aperture of the shell<br>
''Lower image:'' basal view showing the umbilicus]]
Most members have a [[Gastropod shell|shell]], which is in one piece and is typically coiled or spiraled. This coiled shell usually opens on the right hand side (as viewed with the shell [[apex (mollusc)|apex]] pointing upward). Several species have an [[operculum (gastropod)|operculum]] which in many species is a sort of a trapdoor to close the shell. This is usually made of a horn-like material, but in some molluscs it is calcareous. In the land slugs, the shell is reduced or absent, and the body is streamlined.
Some of the more familiar and better-known gastropods are terrestrial (the land snails and slugs), but more than two thirds of all named species live in a marine environment. Marine gastropods include some that are [[herbivore]]s, [[detritus]] feeders, [[predatory]] [[carnivore]]s, [[scavenger]]s, [[parasite]]s, and also a few ciliary feeders, in which the [[radula]] is reduced or absent. In some species which have evolved into endoparasites, such as [[Parenteroxenos doglieli]], many of the standard gastropod features are strongly reduced or absent.
The [[radula]] of a gastropod is usually adapted to the food that a species eats. The simplest gastropods are the [[limpet]]s and [[abalone]]s, herbivores that use their hard radulas to rasp at [[seaweed]]s on rocks.
Many marine gastropods are burrowers, and have soft siphons or tubes that extend from the [[Mantle (mollusc)|mantle]]. Sometimes the shell has a [[siphonal canal]] to accommodate this structure. A siphon enables the animal to draw a small flow of water into their bodies. The siphon is used primarily to "taste" the water, in order to detect prey from a distance. Gastropods with siphons tend to be either predators or scavengers.
Almost all marine gastropods breathe with [[gill]]s, but many freshwater species, and the majority of terrestrial species, have a pallial [[lung]]. The gastropods which have a lung all belong to one group with common descent, the Pulmonata, however, the gastropods with gills are [[paraphyletic]]. The respiratory protein in almost all gastropods is [[hemocyanin]], but a pulmonate family [[Planorbidae]] have [[hemoglobin]] as respiratory protein.
Some [[Opisthobranchia|sea slugs]] are brightly coloured, either as a warning, if they are poisonous or contain stinging cells, or to [[camouflage]] them on the hydroids, sponges and seaweeds on which many of the species are found.
In one large group of sea slugs, the gills are arranged as a rosette of feathery plumes on their backs, which gives rise to their other name, [[nudibranch]]s. Some nudibranchs have smooth or warty backs and have no visible gill mechanism, such that respiration may likely take place directly through the skin.
A few sea slugs are herbivores and some are carnivores. Many have distinct dietary preferences and regularly occur in close association with their food species.
==Geological history==
[[Image:JurassicMarineIsrael.JPG|thumb|250px|Fossil gastropod and attached mytilid [[bivalve]]s on a Jurassic limestone bedding plane in southern [[Israel]].]]
[[Image:Snail1web.jpg|thumb|right|250px|''[[Helix aspersa]]'': a European pulmonate land snail which has commonly been accidentally introduced in many countries throughout the world.]]
{{See also|Evolution of Gastropoda|:fr:Gastropoda (classification phylogénétique)}}
The first gastropods were exclusively marine, with the earliest representatives of the group appearing in the [[Furongian|Late Cambrian]] (''[[Chippewaella]]'', ''[[Strepsodiscus]]''). Early [[Cambrian]] forms like ''[[Helcionella]]'' and ''[[Scenella]]'' are no longer considered gastropods, and the tiny coiled ''[[Aldanella]]'' of earliest Cambrian time is probably not even a mollusk. By the [[Ordovician]] period the gastropods were a varied group present in a range of aquatic habitats. Commonly, [[fossil]] gastropods from the rocks of the early [[Palaeozoic]] era are too poorly preserved for accurate identification. Still, the [[Silurian]] genus ''[[Poleumita]]'' contains fifteen identified species. Fossil gastropods are less common during the Palaeozoic era than [[bivalve]]s.
Most of the gastropods of the Palaeozoic era belong to primitive groups, a few of which still survive today. By the [[Carboniferous]] period many of the shapes we see in living gastropods can be matched in the fossil record, but despite these similarities in appearance the majority of these older forms are not directly related to living forms. It was during the [[Mesozoic]] era that the ancestors of many of the living gastropods evolved.
One of the earliest known terrestrial (land-dwelling) gastropods is ''Maturipupa'' which is found in the [[Coal Measure]]s of the Carboniferous period in [[Europe]], but relatives of the modern land snails are rare before the [[Cretaceous]] period when the familiar ''[[Helix (genus)|Helix]]'' first appeared.
[[Image:Slimaczek.jpg|thumb|left|250px|''[[Cepaea nemoralis]]'': another European pulmonate land snail which has been introduced to many other countries.]]
In rocks of the Mesozoic era gastropods are slightly more common as fossils, their shells are often well preserved. Their fossils occur in beds which were deposited in both freshwater and marine environments. The "Purbeck Marble" of the [[Jurassic]] period and the "Sussex Marble" of the early Cretaceous period which both occur in southern [[England]] are [[limestone]]s containing the tightly packed remains of the pond snail ''[[Viviparus]]''.
Rocks of the [[Cenozoic]] era yield very large numbers of gastropod fossils, many of these fossils being closely related to modern living forms. The diversity of the gastropods increased markedly at the beginning of this era, along with that of the bivalves.
Certain trail-like markings preserved in ancient sedimentary rocks are thought to have been made by gastropods crawling over the soft mud and sand. Although these trails are of debatable origin, some of them do resemble the trails made by living gastropods today.
Gastropod fossils may sometimes be confused with [[ammonite]]s or other shelled [[cephalopod]]s. An example of this is ''[[Bellerophon (mollusc)|Bellerophon]]'' from the limestones of the [[Carboniferous]] period in Europe, the shell of which is planispirally coiled and can be mistaken for the shell of a cephalopod.
Gastropods are one of the groups that record the changes in fauna caused by the advance and retreat of the Ice Sheets during the [[Pleistocene]] epoch.
==Taxonomy==
The [[taxonomy]] of the Gastropoda is under constant revision, and more and more of the old taxonomy is being abandoned as the results of [[DNA]] studies slowly become clearer. Nevertheless some of the older terms such as "opisthobranch" and "prosobranch" are still being used in a descriptive way.
The taxonomy of the Gastropoda as shown in various texts can differ in major ways, and on-going revisions of the higher taxonomic levels are to be expected in the near future.
In the older classification there were four subclasses:
* [[Prosobranchia]] (gills in front of the heart).
* [[Opisthobranchia]] (gills to the right and behind the heart).
* [[Gymnomorpha]] (no shell)
* [[Pulmonata]] (with a lung instead of gills)
According to newer insights based on DNA sequencing, (Ponder & [[David R. Lindberg|Lindberg]], 1997), the taxonomy of the Gastropoda must be rewritten in terms of strictly [[monophyletic]] groups. Integrating these findings into a working [[taxonomy]] will continue to be a challenge in the coming years. At present, it is impossible to give a classification of the Gastropoda that has consistent ranks and also reflects current usage.
Convergent evolution, which appears to exist at especially high frequency within the class Gastropoda, may account for the observed differences between the phylogenies which are obtained from morphological data and the more recent studies based on gene sequences.
New changes in systematics have been made by (Bouchet & Rocroi, 2005).<ref>Bouchet, P.; Rocroi, J.-P. (Ed.); Frýda,J.; Hausdorf,B.; Ponder, W.; Valdes, A.; Warén, A. (2005). Classification and nomenclator of gastropod families. Malacologia: International Journal of Malacology, 47(1-2). ConchBooks: Hackenheim, Germany. ISBN 3-925919-72-4. 397 pp. http://www.vliz.be/Vmdcdata/imis2/ref.php?refid=78278</ref><ref>Poppe G.T. & Tagaro S.P. 2006. The new classification of Gastropods according to Bouchet & Rocroi, 2005. Visaya, février 2006: 10 pp. http://www.journal-malaco.fr/bouchet&rocroi_2005_Visaya.pdf</ref>, resulting in a new taxonomy that is a step closer to the evolutionary history of phyla.
Malacologists currently make do with classifications that are hybrids of the latest existing taxonomy and later revisions published in scientific journals. In the past, the taxonomy of gastropods was largely based on morphological characters of the taxa. The recent advances are more based on molecular characters through research of DNA and RNA. This has made the taxonomical ranks and their hierarchy controversial. The debate about these issues is not likely to end soon.
[[Taxonomy of the Gastropoda (Bouchet & Rocroi, 2005)]]
This new taxonomy has tried to reconcile these recent advances by using '''unranked''' [[clade]]s for taxa above the rank of superfamily (replacing the ranks suborder, order, superorder and subclass), while using the traditional Linnaean approach for all taxa below the rank of superfamily. Whenever monophyly has not been tested or is known to be paraphyletic or polyphyletic, the term "group" or "informal group" has been used. The classification of families into subfamilies is often not well resolved and should be regarded as the best possible hypothesis.
==Proposed classification==
For an even more recent taxonomic scheme please see [[Taxonomy of the Gastropoda (Bouchet & Rocroi, 2005)]]
'''Class Gastropoda''' <small>[[Georges Cuvier|Cuvier]], 1797</small>
'''''Incertæ sedis'''''
*Order [[Bellerophontinaka]] (''fossil'')
*Order [[Mimospirina]] (''fossil'')
'''Subclass [[Eogastropoda]]''' <small>Ponder & Lindberg, 1996</small> (earlier: [[Prosobranchia]])
*Order [[Euomphalida]] <small>de Koninck 1881</small> (''fossil'')
***Superfamily [[Macluritoidea]]
***Superfamily [[Euomphaloidea]]
***Superfamily [[Platyceratoidea]]
*Order [[Patellogastropoda]] <small>[[David R. Lindberg|Lindberg]], 1986</small> (true limpets)
[[Image:CornishLimpets.JPG|thumb|right|Limpets in the intertidal zone in [[Cornwall]], England.]]
**Suborder [[Patellina]] <small>Van Ihering, 1876</small>
***Superfamily [[Patelloidea]] <small>[[Constantine Samuel Rafinesque|Rafinesque]], 1815</small>
**Suborder [[Nacellina]] <small>Lindberg, 1988</small>
***Superfamily [[Acmaeoidea]] <small>Carpenter, 1857</small>
***Superfamily [[Nacelloidea]] <small>[[Johannes Thiele|Thiele]], 1891</small>
**Suborder [[Lepetopsina]] <small>McLean, 1990</small>
***Superfamily [[Lepetopsoidea]] <small>McLean, 1990</small>
'''Subclass [[Orthogastropoda]] <small>Ponder & Lindberg, 1996</small> (earlier [[Prosobranchia]], [[Opisthobranchia]])<br />
'''''Incertæ sedis'''''
*Order [[Murchisoniina]] <small>Cox & Knight, 1960</small> (''fossil'')
*** Superfamily [[Murchisonioidea]] <small>Koken, 1889</small>
*** Superfamily [[Loxonematoidea]] <small>Koken, 1889</small>
*** Superfamily [[Lophospiroidea]] <small>Wenz, 1938</small>
*** Superfamily [[Straparollinoidea]]
** Grade [[Subulitoidea]] <small>Lindström, 1884</small>
Superorder [[Cocculiniformia]] <small>Haszprunar, 1987</small>
***Superfamily [[Cocculinoidea]] <small>[[W.H. Dall|Dall]], 1882</small>
***Superfamily [[Lepetelloidea]] <small>[[W.H. Dall|Dall]], 1882</small> (deep sea limpets)
Superorder ‘Hot Vent Taxa' <small>Ponder & Lindberg, 1997</small>
*Order [[Neomphaloida]] <small>Sitnikova & Starobogatov, 1983</small>
***Superfamily [[Neomphaloidea]] <small>McLean, 1981</small> (hydrothermal vents limpets)
***Superfamily [[Peltospiroidea]] <small>McLean, 1989</small>
Superorder [[Vetigastropoda]] <small>Salvini-Plawen, 1989</small> (limpets)
[[Image:CyprusPlioceneGastropod.JPG|thumb|right|An archaeogastropod from the [[Pliocene]] of [[Cyprus]]. A [[serpulid]] worm is attached.]]
***Superfamily [[Fissurelloidea]] <small>Fleming, 1822</small> (keyhole limpets)
***Superfamily [[Haliotoidea]] <small>[[Constantine Samuel Rafinesque|Rafinesque]], 1815</small> (abalones)
***Superfamily [[Lepetodriloidea]] <small>McLean, 1988</small> (hydrothermal vent limpets)
***Superfamily [[Pleurotomarioidea]] <small>Swainson, 1840</small> (slit shells)
***Superfamily [[Seguenzioidea]] <small>Verrill, 1884</small>
***Superfamily [[Trochoidea (superfamily)|Trochoidea]] <small>[[Constantine Samuel Rafinesque|Rafinesque]], 1815</small> (top shells)
Superorder [[Neritaemorphi]] <small>Koken, 1896</small>
*Order [[Cyrtoneritomorpha]] (''fossil'')
*Order [[Neritopsina]] <small>Cox & Knight, 1960</small>
***Superfamily [[Neritoidea]] <small>[[Jean-Baptiste Lamarck|Lamarck]], 1809</small>
Superorder [[Caenogastropoda]] <small>Cox, 1960</small>
*Order [[Architaenioglossa]] <small>Haller, 1890</small>
***Superfamily [[Ampullarioidea]] <small>[[John Edward Gray|J.E. Gray]], 1824</small>
***Superfamily [[Cyclophoroidea]] <small>[[John Edward Gray|J.E. Gray]], 1847</small> (terrestrials)
*Order [[Sorbeoconcha]] <small>Ponder & Lindberg, 1997</small>
**Suborder [[Discopoda]] <small>P. Fischer, 1884</small>
***Superfamily [[Campaniloidea]] <small>Douvillé, 1904</small>
***Superfamily [[Cerithioidea]] <small>[[André Étienne d'Audebert de Férussac|Férussac]], 1822</small>
**Suborder [[Hypsogastropoda]] <small>Ponder & Lindberg, 1997</small>
**Infraorder [[Littorinimorpha]] <small>Golikov & Starobogatov, 1975</small>
***Superfamily [[Calyptraeoidea]] <small>[[Jean-Baptiste Lamarck|Lamarck]], 1809</small>
***Superfamily [[Capuloidea]] <small>J. Fleming, 1822</small>
***Superfamily [[Carinarioidea]] <small>[[Blainville]], 1818</small> (formerly called Heteropoda)
***Superfamily [[Cingulopsoidea]] <small>Fretter & Patil, 1958</small>
***Superfamily [[Cypraeoidea]] <small>[[Constantine Samuel Rafinesque|Rafinesque]], 1815</small> (cowries)
***Superfamily [[Ficoidea]] <small>Meek, 1864</small>
***Superfamily [[Laubierinoidea]] <small>Warén & Bouchet, 1990</small>
***Superfamily [[Littorinoidea]] <small>(Children), 1834</small> (periwinkles)
***Superfamily [[Naticoidea]] <small>Forbes, 1838</small> (moon shells)
***Superfamily [[Rissooidea]] <small>[[John Edward Gray|J.E. Gray]], 1847</small> (Risso shells) (includes genus ''[[Oncomelania]]'', schistosomiasis transmission vector)
***Superfamily [[Stromboidea]] <small>[[Constantine Samuel Rafinesque|Rafinesque]], 1815</small> (true conchs)
***Superfamily [[Tonnoidea]] <small>[[Henry Suter|Suter]], 1913</small>
***Superfamily [[Trivioidea]] <small>Troschel, 1863</small>
***Superfamily [[Vanikoroidea]] <small>[[John Edward Gray|J.E. Gray]], 1840</small>
***Superfamily [[Velutinoidea]] <small>[[John Edward Gray|J.E. Gray]], 1840</small>
***Superfamily [[Vermetoidea]] <small>[[Constantine Samuel Rafinesque|Rafinesque]], 1815</small> (worm shells)
***Superfamily [[Xenophoroidea]] <small>Troschel, 1852</small> (carrier shells)
**Infraorder [[Ptenoglossa]] <small>J.E. Gray, 1853</small>
***Superfamily [[Eulimoidea]] <small>[[Rodolfo Amando Philippi|Philippi]], 1853</small>
***Superfamily [[Janthinoidea]] <small>[[Jean-Baptiste Lamarck|Lamarck]], 1812</small>
***Superfamily [[Triphoroidea]] <small>[[John Edward Gray|J.E. Gray]], 1847</small>
**Infraorder [[Neogastropoda]] <small>[[Johannes Thiele|Thiele]], 1929</small>
***Superfamily [[Buccinoidea]] (whelks, false tritions)
***Superfamily [[Cancellarioidea]] <small>Forbes & Hanley, 1851</small>
***Superfamily [[Conoidea]] <small>[[Constantine Samuel Rafinesque|Rafinesque]], 1815</small>
***Superfamily [[Muricoidea]] <small>[[Constantine Samuel Rafinesque|Rafinesque]], 1815</small>
Superorder [[Heterobranchia]] <small>[[John Edward Gray|J.E. Gray]], 1840</small>
*Order [[Heterostropha]] <small>P. Fischer, 1885</small>
***Superfamily [[Architectonicoidea]] <small>[[John Edward Gray|J.E. Gray]], 1840</small>
***Superfamily [[Nerineoidea]] <small>[[Karl Alfred von Zittel|Zittel]], 1873</small> (''fossil'')
***Superfamily [[Omalogyroidea]] <small>[[Georg Sars|G.O. Sars]], 1878</small>
***Superfamily [[Pyramidelloidea]] <small>[[John Edward Gray|J.E. Gray]], 1840</small>
***Superfamily [[Rissoelloidea]] <small>[[John Edward Gray|J.E. Gray]], 1850</small>
***Superfamily [[Valvatoidea]] <small>[[John Edward Gray|J.E. Gray]], 1840</small>
*Order [[Opisthobranchia]] <small>[[Alphonse Milne-Edwards|Milne-Edwards]], 1848</small>
**Suborder [[Cephalaspidea]] <small>P. Fischer, 1883</small>
***Superfamily [[Acteonoidea]] <small>[[Alcide d'Orbigny|D'Orbigny]], 1835</small>
***Superfamily [[Bulloidea]] <small>[[Jean-Baptiste Lamarck|Lamarck]], 1801</small>
***Superfamily [[Cylindrobulloidea]] <small>[[Johannes Thiele|Thiele]], 1931</small> (has to be included in the Sacoglossa)
***Superfamily [[Diaphanoidea]] <small>Odhner, 1914</small>
***Superfamily [[Haminoeoidea]] <small>Pilsbry, 1895</small>
***Superfamily [[Philinoidea]] <small>[[John Edward Gray|J.E. Gray]], 1850</small>
***Superfamily [[Ringiculoidea]] <small>[[Rodolfo Amando Philippi|Philippi]], 1853</small>
**Suborder [[Sacoglossa]] <small>Von Ihering, 1876</small>
***Superfamily [[Oxynooidea]] <small>H. & A. Adams, 1854</small>
**Suborder [[Anaspidea]] <small>P. Fischer, 1883</small> (sea hares)
***Superfamily [[Akeroidea]] <small>Pilsbry, 1893</small>
***Superfamily [[Aplysioidea]] <small>[[Jean-Baptiste Lamarck|Lamarck]], 1809</small>
**Suborder [[Notaspidea]] <small>P. Fischer, 1883</small>
***Superfamily [[Tylodinoidea]] <small>[[John Edward Gray|J.E. Gray]], 1847</small>
***Superfamily [[Pleurobranchoidea]] <small>Férussac, 1822</small>
**Suborder [[Sea butterfly|Thecosomata]] <small>[[Blainville]], 1824</small> (sea butterflies)
***Infraorder [[Euthecosomata]]
****Superfamily [[Limacinoidea]]
****Superfamily [[Cavolinioidea]]
***Infraorder [[Pseudothecosomata]]
****Superfamily [[Peraclidoidea]]
****Superfamily [[Cymbulioidea]]
**Suborder [[Gymnosomata]] <small>[[Blainville]], 1824</small> (sea angels)
***Family [[Clionidae]] <small>[[Constantine Samuel Rafinesque|Rafinesque]], 1815</small>
***Family [[Cliopsidae]] <small>Costa, 1873</small>
***Family [[Hydromylidae]] <small>[[Alice Pruvot-Fol|Pruvot-Fol]], 1942</small>
***Family [[Laginiopsidae]] <small>[[Alice Pruvot-Fol|Pruvot-Fol]], 1922</small>
***Family [[Notobranchaeidae]] <small>Pelseneer, 1886</small>
***Family [[Pneumodermatidae]] <small>Latreille, 1825</small>
***Family [[Thliptodontidae]] <small>Kwietniewski, 1910</small>
[[Image:Door snail.jpg|thumb|right|''Cochlodina laminata'' from the family ''Clausiliidae'' or door snails, a small land pulmonate which has a sinistral or left-handed shell, on the trunk of a tree, in woodland, England]]
**Suborder [[Nudibranchia]] <small>[[Blainville]], 1814</small> (nudibranchs)
**Infraorder [[Anthobranchia]] <small>Férussac, 1819</small>
***Superfamily [[Doridoidea]] <small>[[Constantine Samuel Rafinesque|Rafinesque]], 1815</small>
***Superfamily [[Doridoxoidea]] <small>Bergh, 1900</small>
***Superfamily [[Onchidoridoidea]] <small>Alder & Hancock, 1845</small>
***Superfamily [[Polyceroidea]] <small>Alder & Hancock, 1845</small>
**Infraorder [[Cladobranchia]] <small>Willan & Morton, 1984</small>
***Superfamily [[Dendronotoidea]] <small>Allman, 1845</small>
***Superfamily [[Arminoidea]] <small>[[Constantine Samuel Rafinesque|Rafinesque]], 1814</small>
***Superfamily [[Metarminoidea]] <small>Odhner in Franc, 1968</small>
***Superfamily [[Aeolidioidea]] <small>[[John Edward Gray|J.E. Gray]], 1827</small>
*Order [[Pulmonata]] <small>[[Georges Cuvier|Cuvier]] in [[Blainville]], 1814</small> (pulmonates)
**Suborder [[Systellommatophora]] <small>Pilsbry, 1948</small>
***Superfamily [[Onchidioidea]] <small>[[Constantine Samuel Rafinesque|Rafinesque]], 1815</small>
***Superfamily [[Otinoidea]] <small>H. & A. Adams, 1855</small>
***Superfamily [[Rathouisioidea]] <small>Sarasin, 1889</small>
**Suborder [[Basommatophora]] <small>Keferstein in Bronn, 1864</small> (freshwater pulmonates, pond snails)
***Superfamily [[Acroloxoidea]] <small>[[Johannes Thiele|Thiele]], 1931</small>
***Superfamily [[Amphiboloidea]] <small>[[John Edward Gray|J.E. Gray]], 1840</small>
***Superfamily [[Chilinoidea]] <small>H. & A. Adams, 1855</small>
***Superfamily [[Glacidorboidea]] <small>Ponder, 1986</small>
***Superfamily [[Lymnaeoidea]] <small>[[Constantine Samuel Rafinesque|Rafinesque]], 1815</small>
***Superfamily [[Planorboidea]] <small>[[Constantine Samuel Rafinesque|Rafinesque]], 1815</small>
***Superfamily [[Siphonarioidea]] <small>[[John Edward Gray|J.E. Gray]], 1840</small>
**Suborder [[Eupulmonata]] <small>Haszprunar & Huber, 1990</small>
**Infraorder [[Acteophila]] <small>[[W.H. Dall|Dall]], 1885</small> (= formerly Archaeopulmonata)
***Superfamily [[Melampoidea]] <small>Stimpson, 1851</small>
**Infraorder [[Trimusculiformes]] <small>Minichev & Starobogatov, 1975</small>
***Superfamily [[Trimusculoidea]] <small>Zilch, 1959</small>
**Infraorder [[Stylommatophora]] <small>A. Schmidt, 1856</small> (land snails)
**Subinfraorder [[Orthurethra]]
***Superfamily [[Achatinelloidea]] <small>Gulick, 1873</small>
***Superfamily [[Cochlicopoidea]] <small>Pilsbry, 1900</small>
***Superfamily [[Partuloidea]] <small>Pilsbry, 1900</small>
***Superfamily [[Pupilloidea]] <small>Turton, 1831</small>
**Subinfraorder [[Sigmurethra]]
***Superfamily [[Acavoidea]] <small>Pilsbry, 1895</small>
***Superfamily [[Achatinoidea]] <small>Swainson, 1840</small>
***Superfamily [[Aillyoidea]] <small>Baker, 1960</small>
***Superfamily [[Arionoidea]] <small>[[John Edward Gray|J.E. Gray]] in Turnton, 1840</small>
***Superfamily [[Buliminoidea]] <small>Clessin, 1879</small>
***Superfamily [[Camaenoidea]] <small>Pilsbry, 1895</small>
***Superfamily [[Clausilioidea]] <small>Mörch, 1864</small>
***Superfamily [[Dyakioidea]] <small>Gude & Woodward, 1921</small>
***Superfamily [[Gastrodontoidea]] <small>Tryon, 1866</small>
***Superfamily [[Helicoidea]] <small>[[Constantine Samuel Rafinesque|Rafinesque]], 1815</small>
***Superfamily [[Helixarionoidea]] <small>Bourguignat, 1877</small>
***Superfamily [[Limacoidea]] <small>[[Constantine Samuel Rafinesque|Rafinesque]], 1815</small>
***Superfamily [[Oleacinoidea]] <small>H. & A. Adams, 1855</small>
***Superfamily [[Orthalicoidea]] <small>Albers-Martens, 1860</small>
***Superfamily [[Plectopylidoidea]] <small>Moellendorf, 1900</small>
***Superfamily [[Polygyroidea]] <small>Pilsbry, 1894</small>
***Superfamily [[Punctoidea]] <small>Morse, 1864</small>
***Superfamily [[Rhytidoidea]] <small>Pilsbry, 1893</small>
***Superfamily [[Sagdidoidea]] <small>Pilsbry, 1895</small>
***Superfamily [[Staffordioidea]] <small>[[Johannes Thiele|Thiele]], 1931</small>
***Superfamily [[Streptaxoidea]] <small>[[John Edward Gray|J.E. Gray]], 1806</small>
***Superfamily [[Strophocheiloidea]] <small>[[Johannes Thiele|Thiele]], 1926</small>
***Superfamily [[Trigonochlamydoidea]] <small>Hese, 1882</small>
***Superfamily [[Zonitoidea]] <small>Mörch, 1864</small>
***? Superfamily [[Athoracophoroidea]] <small>P. Fischer, 1883</small> (= Tracheopulmonata)
***? Superfamily [[Succineoidea]] <small>Beck, 1837</small> (= Heterurethra)
Other extant classes of the Mollusca are [[Bivalvia]], [[Scaphopoda]], [[Aplacophora]], [[Polyplacophora]], [[Monoplacophora]] and [[Cephalopoda]].
== Footnotes ==
{{reflist}}
==Bibliographic References==
*Shelagh M. Smith - ''Key to the British Marine '''Gastropoda''','' Contains 44 pages plus line drawings about A4 in size. <ref> Published by the Royal Scottish Museum in their Information Series ([[UK]]) in 1974 with no ISBN </ref>
*Paul Jeffery. ''Suprageneric classification of class GASTROPODA''. The Natural History Museum, London, 2001
*Ponder & Lindberg, ''Towards a phylogeny of gastropod molluscs; an analysis using morphological characters''. ''Zoological Journal of the Linnean Society'', '''119''' 83-2651; 1997
*{{cite journal | author=Elpidio A. Remigio and Paul D.N. Hebert| title=Testing the utility of partial COI sequences for phylogenetic (full text on line)| journal=Molecular Phylogenetics and Evolution | year=2003| volume=29| url=http://www.bolinfonet.org/pdf/MPEVsnailpaper.pdf| pages=641–647| doi=10.1016/S1055-7903(03)00140-4}}
==External links==
{{commonscat|Gastropoda}}
* [http://www.conchology.be/ Conchology.be] consult over 2,100,000 figured gastropods and other shells
* [http://www.scholarpedia.org/article/Gastropod_Neuroscience Gastropod Neuroscience]
* [http://www.manandmollusc.net/advanced_introduction/gastropod_taxonomy_1.html Taxonomy]
* [http://www.nhm.ac.uk/research-curation/projects/gastroclass/ Gastropod Classification compiled by Paul Jeffery]
* [http://134.76.36.207:8888/AnimalBase-AniBas-context-root/animalbase-code-user.html International Code of Zoological Nomenclature 4th edition, 2000]
* [http://www.petsnails.co.uk/species/ Gastropods in captivity]
* Reconstructions of fossil gastropods at [http://www.emilydamstra.com/portfolio.php?subcat=14 www.emilydamstra.com]
[[Category:Gastropods| ]]
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