Taxonomy [top]

Kingdom Phylum Class Order Family
Animalia Mollusca Gastropoda Stylommatophora Endodontidae

Scientific Name: Aaadonta angaurana
Species Authority: Solem, 1976

Assessment Information [top]

Red List Category & Criteria: Critically Endangered (Possibly Extinct) B1ab(iii)+2ab(iii) ver 3.1
Year Published: 2012
Date Assessed: 2011-08-22
Assessor(s): Rundell, R.J.
Reviewer(s): Barker, G., Cowie, R., Triantis, K., García, N. & Seddon, M.
Facilitator/Compiler(s): Pippard, H.

This is a minute ground-dwelling snail for which no shells (live or dead) have been found in recent years, despite a survey of its island habitat of Angaur (Ngeaur) in 2005. The species was previously known only from Angaur, where it was collected at a single locality in 1936 by Y. Kondo. The species is assessed as Critically Endangered (Possibly Extinct) as it is believed that it may be extirpated from its only known distribution. Additional surveys of the island are needed to verify whether the species is in fact Extinct, but based on extinctions of endodontids elsewhere in the Pacific (Solem 1976, Solem 1983), optimism is low.

Date last seen: 1936
Previously published Red List assessments:
1996 Data Deficient (DD)
1994 Vulnerable (V)

Geographic Range [top]

Range Description:

The historical geographic range of this species was less than 8 km2 of the heavily modified island of Angaur (Ngeaur), Palau. The species was probably historically more abundant prior to its collection at only a single locality in 1936. Indeed, substantial change had already occurred on that island by that time. No specimens have been found after surveying its island habitat in 2005 (R.J. Rundell 2005, unpublished data, Rundell 2010).

Countries occurrence:
Possibly extinct:
Estimated area of occupancy (AOO) - km2: 0-8
Number of Locations: 1
Lower elevation limit (metres): 1
Upper elevation limit (metres): 200
Range Map: Click here to open the map viewer and explore range.

Population [top]

Population: No information on population size or trends is available, although the species was probably historically more abundant prior to its collection at only a single locality in 1936.
Current Population Trend: Unknown
Additional data:

Habitat and Ecology [top]

Habitat and Ecology:

This is a minute ground-dwelling snail that has been recorded from tropical moist lowland forest.

Systems: Terrestrial
Continuing decline in area, extent and/or quality of habitat: Yes

Use and Trade [top]

Use and Trade: This species is not utilized.

Threats [top]

Major Threat(s):

Destruction and modification of native lowland forest is a major threat to this species. Therefore, it is not surprising that the species has probably been extirpated from the highly modified and deforested island of Angaur. Disruption of the ground, rocks and leaf litter may be of particular significance to this and other endodontid species. Endodontoid land snails are among the most threatened land snails on Pacific Islands in the few places where they still exist (Solem 1983).

Conservation Actions [top]

Conservation Actions: There are no conservation measures in place for this species. Additional surveys of the island are urgently needed to verify whether the species is in fact Extinct.

Citation: Rundell, R.J. 2012. Aaadonta angaurana. The IUCN Red List of Threatened Species 2012: e.T3A2932256. . Downloaded on 09 October 2015.
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