''Allognathus graellsianus'' is a species of

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 gastropod mollusks that have shells (those without shells are known as ...

in the family

Helicidae Helicidae is a large, diverse family of small to large, air-breathing land snails, sometimes called the "typical snails." A number of species in this family are valued as food items, including ''Cornu aspersum'' (formerly ''Helix aspersa'') the b ...

, the true snails. It is

endemic Endemism is the state of a species being found in a single defined geographic location, such as an island, state, nation, country or other defined zone; organisms that are indigenous to a place are not endemic to it if they are also found elsew ...

Mallorca Mallorca, or Majorca, is the largest island in the Balearic Islands, which are part of Spain and located in the Mediterranean. The capital of the island, Palma, is also the capital of the autonomous community of the Balearic Islands. The Bal ...

, one of

Spain , image_flag = Bandera de España.svg , image_coat = Escudo de España (mazonado).svg , national_motto = ''Plus ultra'' (Latin)(English: "Further Beyond") , national_anthem = (English: "Royal March") , i ...

Balearic Islands The Balearic Islands ( es, Islas Baleares ; or ca, Illes Balears ) are an archipelago in the Balearic Sea, near the eastern coast of the Iberian Peninsula. The archipelago is an autonomous community and a province of Spain; its capital is ...

. This taxa is the

type species In zoological nomenclature, a type species (''species typica'') is the species name with which the name of a genus or subgenus is considered to be permanently taxonomically associated, i.e., the species that contains the biological type specimen ...

of the genus ''

Allognathus ''Allognathus'' is a genus of air-breathing land snails, terrestrial pulmonate gastropod mollusks in the family Helicidae, the true snails. The genus is endemic to the Balearic Islands (Western Mediterranean) being present in all major islands an ...

''. The snail lives in cracks in rocks and walls and is only active when it rains.

Description

''A. graellsianus'' presents a thin globose shell. It has from 4 to 4 ½

whorls A whorl ( or ) is an individual circle, oval, volution or equivalent in a whorled pattern, which consists of a spiral or multiple concentric objects (including circles, ovals and arcs). Whorls in nature File:Photograph and axial plane floral d ...

of fast growth, showing 5 bands well separated and usually discontinued. The

aperture In optics, an aperture is a hole or an opening through which light travels. More specifically, the aperture and focal length of an optical system determine the cone angle of a bundle of rays that come to a focus in the image plane. An opt ...

is oval-rounded with a reddish brown reflected

peristome Peristome (from the Greek ''peri'', meaning 'around' or 'about', and ''stoma'', 'mouth') is an anatomical feature that surrounds an opening to an organ or structure. Some plants, fungi, and shelled gastropods have peristomes. In mosses In mosses, ...

. The umbilicus is completely closed. Allognathus graellsianus 3views

Distribution

The species is distributed along northwestern Tramuntana Mountains (western Mallorca), cohabiting in many localities with '' A. hispanicus''.

References

External links

* http://luisjavierchueca.com/research-3/allognathus/ Graellsianus Endemic fauna of the Balearic Islands Molluscs of Europe Gastropods described in 1853 Taxonomy articles created by Polbot {{Helicidae-stub