Sigmurethra is a taxonomic category of air-breathing

land snail A land snail is any of the numerous species of snail that live on land, as opposed to the sea snails and freshwater snails. ''Land snail'' is the common name for terrestrial molluscs, terrestrial gastropod mollusks that have gastropod shell, shel ...

s and

slug Slug, or land slug, is a common name for any apparently shell-less Terrestrial mollusc, 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 ...

s, terrestrial

pulmonate Pulmonata or pulmonates is an informal group (previously an order, and before that, a subclass) of snails and slugs characterized by the ability to breathe air, by virtue of having a pallial lung instead of a gill, or gills. The group inclu ...

gastropod Gastropods (), commonly known as slugs and snails, belong to a large Taxonomy (biology), taxonomic class of invertebrates within the phylum Mollusca called Gastropoda (). This class comprises snails and slugs from saltwater, freshwater, and fro ...

molluscs Mollusca is a phylum of protostome, protostomic invertebrate animals, whose members are known as molluscs or mollusks (). Around 76,000 extant taxon, extant species of molluscs are recognized, making it the second-largest animal phylum ...

. This is an informal group which includes most land snails and

s. The two strong synapomorphies of Sigmurethra are a long pedal gland placed beneath a membrane and retractile tentacles. Several families in this group contain species of snails and slugs that create

love dart A love dart (also known as a gypsobelum, shooting darts, or just as darts) is a sharp, calcium carbonate, calcareous or chitinous Dart (missile), dart which some hermaphroditic land snails and slugs create. Love darts are both formed and stor ...

s. Sigmurethra are known from the

Cretaceous The Cretaceous ( ) is a geological period that lasted from about 143.1 to 66 mya (unit), million years ago (Mya). It is the third and final period of the Mesozoic Era (geology), Era, as well as the longest. At around 77.1 million years, it is the ...

to the Recent periods.

Taxonomy

2005 Taxonomy

In the taxonomy of the Gastropoda by Bouchet & Rocroi, 2005, Sigmurethra is an "Informal Group", a subsection of the Stylommatophora.Bouchet P. & Rocroi J.-P. (Ed.); Frýda J., Hausdorf B., Ponder W., Valdés Á. & Warén A. 2005. ''Classification and nomenclator of gastropod families''. Malacologia: International Journal of Malacology, 47(1-2). ConchBooks: Hackenheim, Germany. . . 397 pp. http://www.vliz.be/Vmdcdata/imis2/ref.php?refid=78278 It consists of the following families: *Superfamily Clausilioidea **Family Clausiliidae ** † Family Anadromidae ** † Family Filholiidae ** † Family Palaeostoidae *Superfamily Orthalicoidea **Family Orthalicidae **Family Cerionidae **Family Coelociontidae ** † Family Grangerellidae **Family Megaspiridae **Family Placostylidae **Family Urocoptidae *Superfamily Achatinoidea **Family Achatinidae **Family Ferussaciidae **Family Micractaeonidae **Family Subulinidae *Superfamily Aillyoidea **Family Aillyidae *Superfamily Testacelloidea **Family Testacellidae **Family Oleacinidae **Family Spiraxidae *Superfamily Papillodermatoidea **Family Papillodermatidae *Superfamily Streptaxoidea **Family Streptaxidae *Superfamily Rhytidoidea **Family Rhytididae **Family

Chlamydephoridae ''Chlamydephorus'' is a genus of air-breathing land slugs, terrestrial pulmonate gastropod mollusks in the family Chlamydephoridae. It is the only genus within the family Chlamydephoridae.Herbert D. G. (1997). "The terrestrial slugs of KwaZul ...

**Family Haplotrematidae **Family Scolodontidae *Superfamily Acavoidea **Family Acavidae **Family Caryodidae **Family Dorcasiidae **Family Macrocyclidae **Family Megomphicidae **Family

Strophocheilidae Strophocheilidae is a Taxonomy (biology), taxonomic family (biology), family of air-breathing land snails, terrestrial molluscs, terrestrial pulmonate gastropod mollusks in the superfamily Acavoidea (according to the Taxonomy of the Gastropoda (B ...

*Superfamily Plectopyloidea **Family Plectopylidae **Family Corillidae **Family Sculptariidae *Superfamily Punctoidea **Family Punctidae ** † Family Anostomopsidae **Family

Charopidae Charopidae is a Taxonomy (biology), taxonomic family (biology), family of small air-breathing land snails (and semi-slugs such as ''Otoconcha dimidiata''), terrestrial molluscs, terrestrial pulmonate gastropod mollusks in the superfamily Punctoi ...

**Family Cystopeltidae **Family Discidae **Family Endodontidae **Family Helicodiscidae **Family Oreohelicidae **Family Thyrophorellidae *Superfamily Sagdoidea **Family Sagdidae

limacoid clade

*Superfamily Staffordioidea **Family Staffordiidae *Superfamily Dyakioidea **Family Dyakiidae *Superfamily Gastrodontoidea **Family Gastrodontidae **Family Chronidae **Family Euconulidae **Family Oxychilidae **Family Pristilomatidae **Family Trochomorphidae **Fossil taxa probably belonging to the Gastrodontoidea ***Subfamily † Archaeozonitinae ***Subfamily † Grandipatulinae ***Subfamily † Palaeoxestininae *Superfamily Parmacelloidea **Family Parmacellidae **Family Milacidae **Family Trigonochlamydidae *Superfamily Zonitoidea **Family Zonitidae *Superfamily Helicarionoidea **Family Helicarionidae **Family Ariophantidae **Family Urocyclidae *Superfamily Limacoidea **Family Limacidae **Family Agriolimacidae **Family Boettgerillidae **Family Vitrinidae

Informal group Sigmurethra continued

Two superfamilies belongs to clade Sigmurethra, but they are not in the limacoid clade. *Superfamily Arionoidea **Family Arionidae **Family Anadenidae **Family Ariolimacidae **Family Binneyidae **Family Oopeltidae **Family Philomycidae *Superfamily

Helicoidea Helicoidea is a Taxonomy (biology), taxonomic Taxonomic rank, superfamily of air-breathing land snails, terrestrial molluscs, terrestrial pulmonate gastropod mollusks in the order (taxonomy), order Stylommatophora. Taxonomy 2017 taxonomy and l ...

**Family

Helicidae Helicidae is a large, diverse family of western Palaearctic, medium to large-sized, air-breathing land snails, sometimes called the "typical snails." It includes some of the largest European land snails, several species are common in anthropoge ...

**Family Bradybaenidae **Family

Camaenidae Camaenidae is a Family (biology), family of air-breathing land snails, terrestrial molluscs, terrestrial pulmonate gastropod mollusks in the superfamily Helicoidea, the typical snails and their allies. This is one of the most diverse families i ...

**Family Cepolidae **Family Cochlicellidae **Family Elonidae **Family Epiphragmophoridae **Family Halolimnohelicidae **Family Helicodontidae **Family Helminthoglyptidae **Family Humboldtianidae **Family Hygromiidae **Family Monadeniidae **Family Pleurodontidae **Family Polygyridae **Family Sphincterochilidae **Family Thysanophoridae **Family Trissexodontidae **Family Xanthonychidae (Families that are exclusively fossil are indicated with a dagger †)

New families after 2005

*Superfamily Streptaxoidea ** Diapheridae - In 2010, Sutcharit et al. (2010)Sutcharit C., Naggs F., Wade C. M., Fontanilla I. & Panha S. (2010). "The new family Diapheridae, a new species of ''Diaphera'' Albers from Thailand, and the position of the Diapheridae within a molecular phylogeny of the Streptaxoidea (Pulmonata: Stylommatophora)". '' Zoological Journal of the Linnean Society'' 160: 1-16. . established a new family Diapheridae within the Streptaxoidea.

2017 Taxonomy

After excluding groups not related, the informal group Sigmurethra becomes suborder Helicina, with the following nine infraorders and a collection of families with no superfamily： *Suborder Helicina ("Non-Achatinoid Clade") **Infraorder Arionoidei **Infraorder Clausilioidei **Infraorder Helicoidei: formed from

and Sagdoidea **Infraorder Limacoidei: formed from original '' limacoid clade'' **Infraorder Oleacinoidei *** Oleacinoidea: formed from original Testacelloidea but with the family Testacellidae excluded; *** Haplotrematoidea: formed from original Rhytidoidea and Haplotrematidae **Infraorder Orthalicoidei **Infraorder Pupilloidei ( Orthurethra) **Infraorder Rhytidoidei: formed by Rhytidoidea merging with contents from Acavoidea. **Infraorder Succineoidei ( Elasmognatha)

References

{{Taxonbar, from=Q3483567 Stylommatophora Extant Cretaceous first appearances Gastropod taxonomy Obsolete gastropod taxa