Taxonomy [top]

Kingdom Phylum Class Order Family
Animalia Mollusca Gastropoda Stylommatophora Partulidae

Scientific Name: Partula affinis
Species Authority: Pease, 1868
Common Name(s):
English Polynesian Tree Snail
Taxonomic Notes: Reclassified by Crampton (1916) as Partula otaheitana affinis. Reinstated as Partula affinis by Johnson, Murray and Clarke (1986).

Assessment Information [top]

Red List Category & Criteria: Critically Endangered B1ab(ii,iv)+2ab(ii,iv) ver 3.1
Year Published: 2009
Date Assessed: 2007-10-20
Assessor(s): Coote, T.
Reviewer(s): Cowie, R. & Seddon, M.B.
After the introduction of the carnivorous snail Euglandina rosea to Tahiti in 1977, native snail populations and species began to disappear rapidly as a result of predation by this species. Partula affinis became rarer and no live individuals were found during the intensive surveys on the main island of Tahiti Nui 2003–2005. The only known population remaining occurs in one valley on the Taiarapu Peninsula of Tahiti.
Previously published Red List assessments:
1996 Extinct (EX)
1994 Extinct (Ex)

Geographic Range [top]

Range Description: This species is endemic to Tahiti. The only known surviving population is in the Faaroa Valley on the Peninsula of Tahiti Iti.
Countries occurrence:
French Polynesia (Society Is.)
Estimated area of occupancy (AOO) - km2: 0-1
Continuing decline in area of occupancy (AOO): Yes
Estimated extent of occurrence (EOO) - km2: 0-1
Number of Locations: 1
Continuing decline in number of locations: Yes
Upper elevation limit (metres): 100
Range Map: Click here to open the map viewer and explore range.

Population [top]

Population: Only one population is known for certain and there may be less than 50 individuals remaining.
Current Population Trend: Decreasing
Additional data:

Habitat and Ecology [top]

Habitat and Ecology: The only known population survives on a patch of the semi-aquatic root plant Alocasia macrorhiza in wet, lowland forest (<100 m altitude), although in the past the species could also be found at higher altitudes.
Systems: Terrestrial

Threats [top]

Major Threat(s): The carnivorous snail Euglandina rosea has reached the valley but appears not to have progressed far in recent years for reasons unknown. This is the only current threat apart from the intrinsic factors associated with small population size.

Conservation Actions [top]

Conservation Actions: The terrain and difficulty of access make conservation measures very difficult. A reserve was built in this valley for the purpose but was quickly destroyed by a rockfall. For the moment, vigilance is the best option. This species exists in the international breeding programme.

Citation: Coote, T. 2009. Partula affinis. The IUCN Red List of Threatened Species 2009: e.T16296A5598191. . Downloaded on 05 October 2015.
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