White desert snail (Eremarionta immaculata)

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White desert snail fact file

• Description
• Biology
• Range
• Habitat
• Status
• Threats
• Conservation
• Find out more
• Glossary
• References
• Print factsheet

White desert snail description

A desert-dwelling mollusc, the aptly named white desert snail (Eremarionta immaculata) is a small terrestrial snail found only in the Riverside Mountains of California, in the United States ^{(2) (4)}. As its name suggests, it has a distinctive white shell ^{(3) (4)}, which is slightly flattened and has a clear umbilicus. The opening of the shell is at a slight angle and is almost circular in shape ⁽³⁾.

The lack of brown bands on the white desert snail’s shell generally distinguishes it from the other members of its genus, which have a brown band around the periphery of the shell ^{(3) (4) (5)}. However, a few juvenile white desert snails have been reported to show faint traces of a narrow brown band ⁽³⁾.

Also known as

white desertsnail.

Synonyms

Micrarionta immaculata.

Size

Shell diameter: 12 - 13 mm ^{(2) (3)}

Shell height: up to 7.3 mm ⁽³⁾

White desert snail biology

For most of the year, the white desert snail remains dormant, hiding beneath the talus. During this time, it withdraws into the protection of its shell, and attaches the opening of the shell to a rock. This seals the white desert snail away from the harsh environment outside, and helps to reduce water loss ^{(2) (4) (5)}.

When the winter rain arrives and the air is moist, the white desert snail becomes active again ^{(2) (5)}, and begins to feed upon detritus and fungi which it scrapes from the rock surfaces. Little else is currently known about the biology of the white desert snail, but it is thought to have a lifespan of up to 12 years ⁽⁵⁾.

White desert snail range

The white desert snail is found only in the Riverside Mountains in eastern Riverside County, California ^{(2) (3) (4)}.

White desert snail habitat

Found among calcium-rich rocks on talus slopes ^{(2) (4) (5)}, the white desert snail occurs in particularly large numbers where there is an abundance of smaller rocks. Talus composed of smaller rocks retains more rainfall and may provide a moister environment for the snail ⁽⁴⁾.

The white desert snail appears to prefer lichen or moss as a substrate, possibly as these provide the snail with food or with a moist surface that increases its ability to absorb water ⁽²⁾.

White desert snail status

The white desert snail is classified as Vulnerable (VU) on the IUCN Red List ⁽¹⁾.

White desert snail threats

Like other Eremarionta species, the white desert snail has a very localised distribution, potentially making it more vulnerable to any threats ^{(2) (4)}. High moisture levels are quite infrequent in its desert environment, limiting the time available for feeding and mating, and so lengthening the time it takes this species to mature and to breed. As a result, the white desert snail population is likely to be slow to recover from increased mortality levels, and slow to re-establish itself in disturbed habitats ⁽²⁾.

Little information is available on the threats to the white desert snail, but its habitat may potentially be affected by quarrying activities ⁽⁵⁾ and by other disturbances such as off-road vehicle use ⁽⁴⁾.

White desert snail conservation

The most beneficial conservation measure for the white desert snail, and for other desert snail species, would be the protection of its existing habitat and populations ^{(2) (4)}. For example, sites where this species occurs should be protected from human disturbances that could physically alter the talus slopes ⁽⁴⁾.

Further surveys need to be conducted to better establish the status of the white desert snail and to investigate its habitat preferences ⁽⁴⁾. Surveys for this and other sensitive species are also being conducted at the Agnes Wilson Quarry and other potential quarry sites, to ensure that this small snail will not be affected by quarrying activities ⁽⁵⁾.

Find out more

Find out more about mollusc conservation:

• Kay, E.A. (1995) The Conservation Biology of Molluscs. IUCN, Gland, Switzerland. Available at:
  http://data.iucn.org/dbtw-wpd/edocs/ssc-op-009.pdf

More information on conservation in California:

• California Department of Conservation:
  http://www.conservation.ca.gov/Index/Pages/Index.aspx

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This species information was authored as part of the ARKive and Universities Scheme.

Glossary

Detritus

Litter formed from fragments of dead material.

Genus

A category used in taxonomy, which is below ‘family’ and above ‘species’. A genus tends to contain species that have characteristics in common. The genus forms the first part of a ‘binomial’ Latin species name; the second part is the specific name.

Lichen

A composite organism made up of a fungus in a co-operative partnership with an alga. Owing to this partnership, lichens can thrive in harsh environments such as mountaintops and polar regions. Characteristically forms a crustlike or branching growth on rocks or tree trunks.

Molluscs

A diverse group of invertebrates, mainly marine, that have one or all of the following; a horny, toothed ribbon in the mouth (the radula), a shell covering the upper surface of the body, and a mantle or mantle cavity with a type of gill. Includes snails, slugs, shellfish, octopuses and squid.

Talus

A sloping mass of loose rock fragments at the foot of a cliff.

Umbilicus

In gastropod molluscs, such as snails, a depression or hole on the underside of the shell, at the centre of the whorls (the spirals or coils of the shell). It is present in many but not all snail species.

References

1. IUCN Red List (September, 2012)
   http://www.iucnredlist.org/
2. Wiesenborn, W.D. (2003) White desertsnail, Eremarionta immaculata (Gastropoda: Pulmonata), activity during daylight after winter rainfall. The Southwestern Naturalist, 48(2): 202-207.
3. Willet, G. (1937) A new land shell from the Riverside Mountains, Colorado Desert. Bulletin of The Southern California Academy of Sciences, 36: 6-7.
4. Weisenborn, W.D. (2000) Abundance and dispersion of shells of the white desertsnail, Eremarionta immaculata (Gastropoda: Pulmonata). The Southwestern Naturalist, 45(4): 450-455.
5. U.S. Bureau of Reclamation, Lower Colorado Region (1996) Description and Assessment of Operations, Maintenance, and Sensitive Species of the Lower Colorado River. U.S. Bureau of Reclamation, Lower Colorado Region, Boulder City, Nevada. Available at:
   http://www.usbr.gov/lc/region/g2000/assess/chapter4.htm