|Scientific Name:||Aaadonta fuscozonata|
|Species Authority:||(Beddome, 1889)|
|Infra-specific Taxa Assessed:|
Helix fuscozonata Beddome, 1889
Patula fuscozonata (Beddome, 1889)
|Taxonomic Notes:||Two subspecies have been described, namely: fuscozonata s.str. and depressa Solem 1976.|
|Red List Category & Criteria:||Endangered B1ab(ii,iii)+2ab(ii,iii) ver 3.1|
|Reviewer(s):||Barker, G. & Seddon, M.|
This species is assessed as Endangered, based on its limited extent of occurrence and area of occupancy, as well as a continuing decline in the area of occupancy due to the loss in extent and quality of its habitat. Based on recent survey work, this species may be extinct on the islands from which it was previously known (i.e. Koror and Peleliu). Only a very small number of specimens have been found recently, on Ngemelis and four northern Rock Islands, despite surveys of available native habitat throughout the archipelago.
|Previously published Red List assessments:||
The historical geographic range of this species was less than 20 km2, having been recorded from the islands of Koror (Oreor) and Peleliu (Beliliou) (Solem 1976) based on collections made late in the 19th century and in 1936. The species was likely historically more abundant prior to its collection in 1936. Indeed, substantial change (i.e. human development, including increased human population in villages and mining operations) had already occurred on Koror and Peleliu by that time. The area of occupancy for this species is now estimated at less than 2 km2, since few specimens have been found recently (Rundell 2005 and 2007, unpublished data) in very small areas on very small islands of Ngemelis and on four northern Rock Islands; the species may be extinct on Koror and Peleliu as recent surveys have not detected populations persisting there.
|Estimated area of occupancy (AOO) - km2:||2|
|Continuing decline in area of occupancy (AOO):||Yes|
|Estimated extent of occurrence (EOO) - km2:||20|
|Number of Locations:||5|
|Lower elevation limit (metres):||1|
|Upper elevation limit (metres):||200|
|Range Map:||Click here to open the map viewer and explore range.|
This is a minute ground-dwelling snail for which only ten live shells were found in 2005 and 2007 in Palau (Rundell 2005 and 2007, unpublished data): on Ngemelis one live snail was found, and at single localities on four northern Rock Islands were found three, two, three and one live snails respectively.
This species was earlier reported from Koror (Beddome 1889, Solem 1976) and Peleliu. Thirty-eight specimens in total were collected at the above localities in 1936 by Y. Kondo (Solem 1976). Nonetheless, no specimens were found in surveys of Koror and Peleliu during 2003, 2005 and 2007 (Rundell 2007 unpublished data, Rundell 2005 and 2010).
|Current Population Trend:||Decreasing|
|Habitat and Ecology:||This species is found in tropical moist lowland forest.|
|Continuing decline in area, extent and/or quality of habitat:||Yes|
|Use and Trade:||This species is not utilized.|
This species is threatened by destruction and modification of native lowland forest. Therefore it is not surprising that the species has likely been extirpated from the highly modified and deforested island of Koror and from the highly modified island of Peleliu, whose forest was burned in World War II with flamethrowers (Hinz 1995, Crombie and Pregill 1999). Disruption of the ground, rocks and leaf litter may be of particular significance to this and other endodontoid species. The species currently appears to be extant on five different islands, but all of these islands are very small, and therefore the few individuals living there are subject to sudden, rapid and negative environmental change at any time (e.g. introduction of an invasive predatory flatworm). Endodontoid land snails are among the most threatened land snails on Pacific Islands in the few places where they still exist (Solem 1983) and therefore the fact that this species is still extant is important. This species is in need of conservation attention.
This species is not protected. Conservation action is urgently required, for example protection of its habitat.
Field work to define the current distribution of this species, as well as research on its population status and trends, is required. Identification of priority sites for species conservation (e.g. key biodiversity areas that include threatened land snails) and reducing the impacts of human activities, especially on the small islands, is also urgently needed. The Palau Conservation Society has been supportive of recent land snail survey work in Palau.
Beddome, R.H. 1889. Descriptions of land-shells from the Island of Koror, Pelew Group. Proceedings of the Zoological Society of London 1889: 112-116.
Colin, PL. 2009. Marine Environments of Palau. Indo-Pacific Press, San Diego.
Crombie, R.I. and Pregill, G.K. 1999. A checklist of the herpetofauna of the Palau Islands (Republic of Belau), Oceania. Herpetological Monographs 13: 29-80.
Hinz, E. 1995. Pacific Island Battlegrounds of World War II: Then and Now. The Bess Press, Honolulu.
IUCN. 2012. IUCN Red List of Threatened Species (ver. 2012.2). Available at: http://www.iucnredlist.org. (Accessed: 17 October 2012).
Rundell, RJ. 2005. The land snails of Belau: Survey of the 16 states.
Rundell, RJ. 2008. Cryptic diversity, molecular phylogeny and biogeography of the rock- and leaf litter-dwelling land snails of Belau (Republic of Palau, Oceania). Philosophical Transactions of the Royal Society of London B 363: 3401-3412.
Rundell, RJ. 2010. Diversity and conservation of the land snail fauna of the western Pacific islands of Belau (Republic of Palau, Oceania). American Malacological Bulletin 28: 81-90.
Smith, B.D. 1993. Working list of the terrestrial gastropods of Palau, Caroline Islands. Working List No. 4. Dickinson Memorial Mollusc Collection, Marine Laboratory, University of Guam.
Solem, A. 1976. Endodontoid land snails from Pacific islands (Mollusca: Pulmonata: Sigmurethra). Part I. Family Endodontidae. Field Museum of Natural History, Chicago.
Solem, A. 1983. Endodontoid land snails from Pacific islands (Mollusca: Pulmonata: Sigmurethra). Part II. Families Punctidae and Charopidae. Zoogeography. Field Museum of Natural History, Chicago.
|Citation:||Rundell, R.J. 2012. Aaadonta fuscozonata. The IUCN Red List of Threatened Species 2012: e.T5A3084990. . Downloaded on 07 February 2016.|
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