Achatinella mustelina
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Achatinella mustelina |
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| Mighels , 1845 |
Achatinella mustelina is a species of snail from the genus Achatinella , a group of nocturnal, viviparous tree snails thatare endemic to the Hawaiian island of Oahu .
description
Achatinella mustelina has a case length of 2.6 centimeters and a case diameter of 1.5 centimeters. The casing is elongated ovoid and right or left wound. It has up to seven convex turns, edged up along the seam, and a tiny navel. The case mouth is elongated ovoid. The mouth edge is thickened, simple and pointed. The short, thick, slightly twisted spindle almost completely closes the navel with a callus. The color of the case varies. Often the surface is dark brown with a light stripe on the edge of the turns along the seam, or white with numerous brown or black transverse lines.
The hermaphrodite snail gives birth to live young, and only one young in a litter . The snail reaches sexual maturity at 4 years of age and can live to be 10 years old. She can become pregnant up to four times a year and thus give birth to up to 28 young animals in her lifetime.
distribution
Achatinella mustelina lives in the Waiʻanae Mountains on the Hawaiian island of Oʻahu. At the beginning of the 1990s, this species was the last of its genus, which was still found in large numbers in some places, but with a rapidly decreasing trend. Like all representatives of the genus without exception, its existence is severely endangered. Probable causes of the decline are excessive collection by snail collectors, the stalking by introduced pigs and rats, the clearing of forests and invasive plant species such as Clidemia hirta and Dicranopteris linearis , which prevent the regrowth of the food trees that are indispensable for the snails. The introduced ant species Pheidole megacephala , the garlic gloss snail ( Oxychilus alliarius ) and the rosy wolf snail ( Euglandina rosea ) also hunt Achatinella snails. While Achatinella mustelina only gives birth to a single young at a time - up to four per year - the rosy wolf snail lays up to 600 eggs in one clutch and can thus reproduce much faster.
The University of Hawaii , in cooperation with the US Army, is trying to keep the snail, known in Hawaii as the kahuli tree snail, at least in captivity and has had a rat- and predator-proof cage the size of a basketball court built.
literature
- SM Wells, RM Pyle & NM Collins: IUCN Invertebrate Red Data Book . International Union for the Conservation of Nature and Natural Resources, 1983, ISBN 2880326028 .
- Henry A. Pilsbry and C. Montague Cooke: Manual of Conchology. Structural and Systematic. Volume XXII. Achatinellidae . Conchological Department, Philadelphia, 1912-1914.
- EW Thwing, Henry A. Pilsbry, and C. Montague Cooke: Occasional papers of Bernice P. Bishop Museum (1907-1917) . Bernice P. Bishop Museum.
- US Fish and Wildlife Service (1992): Recovery Plan for the Oʻahu Tree Snails of the Genus Achatinella (PDF; 17.1 MB) . US Fish and Wildlife Service, Portland, Oregon, Article 64 pages, Appendix 64, 5 figures.
Web links
- Achatinella must elina in the endangered Red List species the IUCN 2006. Posted by: Mollusc Specialist Group, 1996. Accessed February 18, 2013.
Individual evidence
- ^ John R. Platt: US Army Protects Critically Endangered Hawaiian Snails from Invasive Predators . Scientific American, February 15, 2012.