Clausiliidae


Clausiliidae, also known by their common name the door snails, are a taxonomic family of small, very elongate, mostly left-handed, air-breathing land snails, sinistral terrestrial pulmonate gastropod mollusks.
With about 1,300 species recent and fossil, this belong among the most diverse families of land gastropods.
Most species of Clausiliidae have an anatomical structure known as a clausilium, which enables the snail to close off the aperture of the shell with a sliding "door".

Shell description

Almost all the species of snails in the family of door snails are left-handed, which is an uncommon feature in gastropod shells in general.
These snails have shells which are extremely high-spired, with numerous whorls.
The shells tend to be club-shaped, tapering at both ends to a rounded nub. The aperture usually has visible folds.

The clausilium

Clausiliids are also very unusual among pulmonate gastropods in that most of them have a "door" or clausilium. The clausilium is not the same thing as an operculum, which does not exist at all in pulmonate gastropods.
The clausilium is a calcareous structure, tongue-shaped or spoon-shaped, which can close the aperture of the snail shell to protect the soft parts against predation by animals such as carnivorous beetle larvae. The narrow end of the clausilium slides in the grooves that are formed by the folds on the inside of the shell.

Anatomy

In this family, the number of haploid chromosomes lies between 21 and 30.

Taxonomy

The type genus is Clausilia Draparnaud, 1805.
The family Clausiliidae is classified within the informal group Sigmurethra, itself belonging to the clade Stylommatophora within the clade Eupulmonata.

2005 taxonomy

The taxonomy of the Gastropoda by Bouchet & Rocroi, 2005 recognizes subfamilies as follows:
subfamily Clausiliinae Gray, 1855
subfamily Alopiinae A. J. Wagner, 1913
subfamily Baleinae A. J. Wagner, 1913 - synonyms: Laciniariini H. Nordsieck, 1963; Tristaniinae Schileyko, 1999
subfamily † Constrictinae H. Nordsieck, 1981
subfamily Garnieriinae C. Boettger, 1926
subfamily † Eualopiinae H. Nordsieck, 1978
subfamily Laminiferinae Wenz, 1923
subfamily Mentissoideinae Lindholm, 1924
subfamily Neniinae Wenz, 1923 - Neniastrinae H. B. Baker, 1930
subfamily Phaedusinae A. J. Wagner, 1922
subfamily Serrulininae Ehrmann, 1927

Genera

Genera include:

Clausiliinae

tribe Clausiliini
tribe Gracillariini
Alopiinae
tribe Alopiini
tribe Cochlodinini
tribe Delimini
tribe Medorini H. Nordsieck, 1997
tribe Montenegrinini
Fossil subfamily Constrictinae contains genera:
Fossil subfamily Eualopiinae contains genera:
tribe † Eualopiini
tribe † Rillyini
tribe Phaedusini
tribe Megalophaedusini
tribe ?
Although non-marine molluscs appear to be exceptionally vulnerable to extinction, the IUCN Red list listed only 9 species from this family.