Basommatophora was a term that was previously used as a taxonomic informal group, a group of

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 G ...

s within the informal group Pulmonata, the air-breathing slugs and snails. According to the

taxonomy of the Gastropoda (Bouchet & Rocroi, 2005) The taxonomy of the Gastropoda as it was revised in 2005 by Philippe Bouchet and Jean-Pierre Rocroi is a system for the scientific classification of gastropod mollusks. (Gastropods are a taxonomic class of animals which consists of snails and s ...

, whenever

monophyly 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 ...

has not been tested, or where a traditional

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 n ...

of gastropods has now been discovered to be paraphyletic or

polyphyletic A polyphyletic group is an assemblage of organisms or other evolving elements that is of mixed evolutionary origin. The term is often applied to groups that share similar features known as homoplasies, which are explained as a result of conver ...

, the term "group" or "informal group" was used. Basommatophora are known from the

Carboniferous The Carboniferous ( ) is a geologic period and system of the Paleozoic that spans 60 million years from the end of the Devonian Period million years ago ( Mya), to the beginning of the Permian Period, million years ago. The name ''Carbonifero ...

to the Recent periods.(in Czech) Pek I., Vašíček Z., Roček Z., Hajn. V. & Mikuláš R.: ''Základy zoopaleontologie''. - Olomouc, 1996. 264 pp., . Most of the families in this suborder are air-breathing freshwater snails. The three most abundant families in terms of number of species are, the Lymnaeidae (pond snails), the Planorbidae (ramshorn snails) and the Physidae (pouch or bubble snails). These are found in ponds, creeks, ditches, and shallow lakes nearly worldwide. The

Siphonariidae Siphonariidae, also known as false limpets, are a taxonomic family of small to medium-sized air-breathing sea snails, marine and brackish water pulmonate gastropod molluscs. __TOC__ Shell description Empty siphonariid limpet shells can be dis ...

on the other hand are unusual in that they have secondarily returned to the sea, and are now sea snails,

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 the various groups called "limpets" descended indep ...

-like marine gastropods which live in the rocky intertidal zone but which still breathe air and become active at low tide. The single species in the family Amphibolidae is archaic and retains an operculum. It lives at such a high tidal level that it could perhaps be considered semi-terrestrial. Members of the family Chilinidae are confined to temperate parts of South America, and the

Latiidae ''Latia'' is a genus of very small, air-breathing freshwater snails or limpets, aquatic pulmonate gastropod molluscs in the superfamily Chilinoidea. ''Latia'' is the only genus in the family Latiidae. Species in this genus are the only ...

are limpet-like and confined to New Zealand. Basommatophorans are characterized by having their eyes located at the base of their non-retractile tentacles, rather than at the tips, as in the true land snails Stylommatophora. The majority of basommatophorans have shells that are thin, translucent, and relatively colorless, and all except Amphibola lack an operculum.

Taxonomy

1997 taxonomy

In the older

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. The full name of the work in which this taxonom ...

the suborder Basommatophora consisted of the families : * Acroloxidae Thiele, 1931 * Amphibolidae J. E. Gray, 1840 - only one species '' Amphibola crenata'' *

Ancylidae Ancylini is a tribe of small, freshwater, air-breathing limpets, aquatic pulmonate gastropod mollusks in the family Planorbidae, the ram's horn snails and their allies. This tribe used to be treated as a family; the current taxonomic placemen ...

* Carychiidae Jeffreys, 1830 * Chilinidae * Lancidae *

Lymnaeidae Lymnaeidae, common name the pond snails, is a taxonomic family of small to large air-breathing freshwater snails, aquatic pulmonate gastropod mollusks, that belong to the clade Hygrophila. Lymnaeidae is the only family within the superf ...

Rafinesque, 1815 * Otinidae H. Adams & A. Adams, 1855 *

Physidae Physidae, common name the bladder snails, is a monophyletic taxonomic family of small air-breathing freshwater snails, aquatic pulmonate gastropod molluscs in the superfamily Lymnaeoidea .MolluscaBase eds. (2021). MolluscaBase. Physida ...

Fitzinger, 1833 *

Planorbidae Planorbidae, common name the ramshorn snails or ram's horn snails, is a family of air-breathing freshwater snails, aquatic pulmonate gastropod molluscs. Unlike most molluscs, the blood of ram's horn snails contains iron-based hemoglobin instea ...

Rafinesque, 1815 *

J. E. Gray, 1840 *

Trimusculidae ''Trimusculus'' is a genus of medium-sized air-breathing sea snails or false limpets, marine pulmonate gastropod molluscs in the family Trimusculidae. ''Trimusculus'' is the only genus in the family Trimusculidae. Trimusculidae, the butt ...

Zilch, 1959

2005 taxonomy

The informal group Basommatophora contains the following superfamilies and the

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, ...

Hygrophila (according to the

Taxonomy of the Gastropoda (Bouchet & Rocroi, 2005) The taxonomy of the Gastropoda as it was revised in 2005 by Philippe Bouchet and Jean-Pierre Rocroi is a system for the scientific classification of gastropod mollusks. (Gastropods are a taxonomic class of animals which consists of snails and s ...

): *Superfamily Amphiboloidea Gray, 1840 **Family Amphibolidae Gray, 1840 *Superfamily

Siphonarioidea Siphonarioidea is a taxonomic superfamily of air-breathing sea snails or false limpets, marine gastropod mollusks in the clade Panpulmonata. Distribution The Siphonarioidea are broadly distributed across the globe, however they are known t ...

Gray, 1827 **Family

Gray, 1827 ** † Family

Acroreiidae † Acroreiidae is an extinct family of air-breathing snails, pulmonate gastropod mollusks in the superfamily Siphonariidae. The living siphonariids are all marine pulmonates, false sea limpets that breathe air. Taxonomy The family Acroreiida ...

Cossmann, 1893 ; Clade Hygrophila *Superfamily Chilinoidea Dall, 1870 **Family Chilinidae Dall, 1870 **Family

Hutton, 1882 *Superfamily Acroloxoidea Thiele, 1931 **Family Acroloxidae Thiele, 1931 *Superfamily

Lymnaeoidea Lymnaeoidea, common name the pond snails, is a taxonomic superfamily of small to large air-breathing freshwater snails, aquatic pulmonate gastropod mollusks, that belong to the superorder Hygrophila.MolluscaBase eds. (2020). MolluscaBase ...

Rafinesque, 1815 **Family

Rafinesque, 1815 *Superfamily

Planorboidea Planorboidea is a superfamily of air-breathing freshwater snails, aquatic pulmonate gastropod mollusks. All of the gastropods in this superfamily are sinistral in shell coiling. The monophyly of Planorboidea was confirmed by Albrecht et al ...

Rafinesque, 1815 **Family

Fitzinger, 1833 The family

has been reduced in the new taxonomy to the status of tribe Ancylini

Rafinesque Constantine Samuel Rafinesque-Schmaltz (; October 22, 1783September 18, 1840) was a French 19th-century polymath born near Constantinople in the Ottoman Empire and self-educated in France. He traveled as a young man in the United States, ultimat ...

, 1815 of the subfamily Planorbinae

, 1815 of the family

, 1815. The family Carychiidae has been reduced in this taxonomy to the status of subfamily Carychiinae Jeffreys, 1830 of the family

Ellobiidae Ellobiidae, common name the hollow-shelled snails, is a family of small air-breathing land snails, terrestrial pulmonate gastropod mollusks in the clade Eupulmonata.Bouchet, P. (2012). Ellobiidae. Accessed through: World Register of Marine Spe ...

L. Pfeiffer, 1854 (1822). The family Lancidae has been reduced in this taxonomy to the status of subfamily Lancinae Hannibal, 1814 of the family

, 1815.

2010 taxonomy

More recently, the Basommatophora was found to be

, and so Jörger et al. (2010)Jörger K. M., Stöger I., Kano Y., Fukuda H., Knebelsberger T. & Schrödl M. (2010). "On the origin of Acochlidia and other enigmatic euthyneuran gastropods, with implications for the systematics of Heterobranchia". ''

BMC Evolutionary Biology ''BMC Ecology and Evolution'' (since January 2021), previously ''BMC Evolutionary Biology'' (2001–2020), is a peer-reviewed open access scientific journal covering all fields of evolutionary biology, including phylogenetics and palaeontology ...

'' 10: 323. . moved its three members, the (superfamily

, superfamily Amphiboloidea, and clade Hygrophila) into a new taxon,

Panpulmonata Panpulmonata is a taxonomic clade of snails and slugs in the clade Heterobranchia within the clade Euthyneura. Panpulmonata was established as a new taxon by Jörger et al. in October 2010. The older name "Pulmonata" referred to a group of gas ...

References

{{Taxonbar, from=Q587355 Obsolete gastropod taxa Carboniferous first appearances