The insular birddrop or

San Clemente Island San Clemente Island (Tongva: ''Kinkipar''; Spanish: ''Isla de San Clemente'') is the southernmost of the Channel Islands of California. It is owned and operated by the United States Navy, and is a part of Los Angeles County. It is administered b ...

blunt-top snail, scientific name ''Vertigo clementina'', is a

species In biology, a species is the basic unit of Taxonomy (biology), classification and a taxonomic rank of an organism, as well as a unit of biodiversity. A species is often defined as the largest group of organisms in which any two individuals of ...

of small, air-breathing land snail, a

terrestrial Terrestrial refers to things related to land or the planet Earth. Terrestrial may also refer to: * Terrestrial animal, an animal that lives on land opposed to living in water, or sometimes an animal that lives on or near the ground, as opposed to ...

gastropod

mollusk Mollusca is the second-largest phylum of invertebrate animals after the Arthropoda, the members of which are known as molluscs or mollusks (). Around 85,000 extant species of molluscs are recognized. The number of fossil species is es ...

in the family

Vertiginidae Vertiginidae, common name the whorl snails, is a family of minute, air-breathing land snails, terrestrial pulmonate gastropod molluscs or micromollusks in the superfamily Pupilloidea. Distribution The distribution of the Vertiginidae is in ...

.''Sterkia clementina''.

NatureServe NatureServe, Inc. is a non-profit organization based in Arlington County, Virginia, US, that provides proprietary wildlife conservation-related data, tools, and services to private and government clients, partner organizations, and the public. Nat ...

Explorer, accessed 1 August 2010. (Incorrectly placed within Chondrinidae in the 2006 IUCN Red List.) MolluscaBase eds. (2023). MolluscaBase. Vertigo clementina. Accessed through: World Register of Marine Species at: https://www.marinespecies.org/aphia.php?p=taxdetails&id=1431022 on 2023-02-08

Description

(Original description) The shell is very minute, narrowly perforate and cylindrical. It is pale horn colored, transparent, with rather obtuse apex. The shell contains 5½

whorl 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 flo ...

s, regularly increasing and moderately rounded. They contain a rather deep suture. The shell is smooth, with few microscopic striae, somewhat shining. The body whorl occupies rather more than two-fifths of the length of the shell and is somewhat ascending to 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 ...

, with a slight, revolving impression on the middle of its last half, ending at the auricle. There is a very slight, flat, crest-elevation near the margin, only in the lower part. The aperture is lateral, scarcely oblique, subovate with the palatal margin slightly flattened, the upper part of same somewhat sinuous. The peristome is a little expanded with a slightly thickened outer lip just at the margin. The shell contains six white lamellae: two on the apertural wall, the apertural, typical, and a rather long supra-apertural, ending in a callus at the upper termination of the palatal margin. The horizontal columellar margin is typical. The basal is very small, nodule-like and deep seated. The two palatals are typical, the inferior a little longer. Sterki, V. (1890). A new Pupa. The Nautilus. 4(4): 44, pl. 1, fig. 4
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Distribution

This species 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 els ...

to the State of

California California is a state in the Western United States, located along the Pacific Coast. With nearly 39.2million residents across a total area of approximately , it is the most populous U.S. state and the 3rd largest by area. It is also the ...

, U.S.A. The survival of this species is "near threatened".

References

External links

Vanatta, E. G. (1916). Bifidaria clementina oldroydae, n. var. The Nautilus. 30(4): 48
{{Taxonbar, from=Q946788 clementina Fauna of the United States Gastropods described in 1890