Pachnodus oxoniensis


Taxonomy [top]

Kingdom Phylum Class Order Family

Scientific Name: Pachnodus oxoniensis
Species Authority: Gerlach, 1994

Assessment Information [top]

Red List Category & Criteria: Critically Endangered B1ab(iii)+2ab(iii) ver 3.1
Year Published: 2009
Date Assessed: 2006-01-11
Assessor(s): Gerlach, J.
Reviewer(s): Miller, R.M., Pollock, C.M. & Seddon, M.B.
This species is restricted to a very small range; its EOO and AOO are both estimated to be 3 km², and it is found in only 1 location. Within this area the population is stable, but vulnerable to habitat deterioration and habitat change resulting from climate change (changes in rainfall patterns), as well as ongoing habitat degradation caused by the impacts of invasive alien plant species (e.g., Cinnamomum verum).

Geographic Range [top]

Range Description: A Seychelles endemic, this snail is known only from Silhouette island and has an estimated extent of occurrence (EOO) and area of occupancy (AOO) of just 3 km².
Seychelles (Seychelles (main island group))
Range Map: Click here to open the map viewer and explore range.

Population [top]

Population: Population estimates showed 423,000 individuals in 2005.
Population Trend: Stable

Habitat and Ecology [top]

Habitat and Ecology: This is an arboreal species restricted to high moss forest, above 450 m.
Systems: Terrestrial

Threats [top]

Major Threat(s): Pachnodus oxoniensis is vulnerable to habitat deterioration and habitat change resulting from climate change (changes in rainfall patterns), as well as habitat degradation caused by the impacts of invasive alien species (e.g., Cinnamomum verum).

Conservation Actions [top]

Conservation Actions: No conservation measures are in place. The forest areas of Silhouette should be protected, and invasive species must be controlled throughout the Seychelles.

Bibliography [top]

Gerlach, J. 2006. Terrestrial and Freshwater Mollusca of the Seychelles Islands. Backhuys, Leiden.

Gerlach, J., Matyot, P. and Samways, M.J. 2005. Developing strategies for invertebrate conservation, the case of the Seychelles islands. Phelsuma: 9-12.

IUCN. 2009. IUCN Red List of Threatened Species (ver. 2009.2). Available at: (Accessed: 3 November 2009).

Citation: Gerlach, J. 2009. Pachnodus oxoniensis. The IUCN Red List of Threatened Species. Version 2015.2. <>. Downloaded on 02 September 2015.
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