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Aaadonta angaurana 

Scope:Global
Status_ne_offStatus_dd_offStatus_lc_offStatus_nt_offStatus_vu_offStatus_en_offStatus_cr_onStatus_ew_offStatus_ex_off

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.
Justification:

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 No specimens have been found after surveying its island habitat in 2005 (R.J. Rundell 2005, unpublished data, Rundell 2010).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:
Palau
Additional data:
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.

Classifications [top]

1. Forest -> 1.6. Forest - Subtropical/Tropical Moist Lowland
suitability: Suitable  major importance:Yes

In-Place Research, Monitoring and Planning
In-Place Land/Water Protection and Management
In-Place Species Management
In-Place Education
5. Biological resource use -> 5.3. Logging & wood harvesting -> 5.3.5. Motivation Unknown/Unrecorded
♦ timing: Ongoing ♦ scope: Unknown ♦ severity: Unknown ⇒ Impact score: Unknown 
→ Stresses
  • 1. Ecosystem stresses -> 1.2. Ecosystem degradation

1. Research -> 1.2. Population size, distribution & trends

Bibliography [top]

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 angaurana. The IUCN Red List of Threatened Species 2012: e.T3A2932256. . Downloaded on 27 July 2016.
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