Taxonomy [top]

Kingdom Phylum Class Order Family
Animalia Mollusca Gastropoda Stylommatophora Streptaxidae

Scientific Name: Priodiscus serratus
Species Authority: (Adams, 1868)

Assessment Information [top]

Red List Category & Criteria: Vulnerable B1ab(iii)+2ab(iii); D2 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.
Although population densities are high and the populations are stable, this species has a restricted range and populations are vulnerable to habitat deterioration. Such deterioration is ongoing, caused by invasive plant species such as Cinnamomum verum. Both the EOO and AOO are estimated at 14 km², and the species is found in just 10 locations.

Geographic Range [top]

Range Description: This snail species is endemic to Silhouette island, in the Seychelles islands. Both its extent of occurrence (EOO) and area of occupancy (AOO) are estimated to be 14 km².
Countries occurrence:
Seychelles (Seychelles (main island group))
Estimated area of occupancy (AOO) - km2: 14
Continuing decline in area of occupancy (AOO): No
Extreme fluctuations in area of occupancy (AOO): No
Estimated extent of occurrence (EOO) - km2: 14
Continuing decline in extent of occurrence (EOO): No
Extreme fluctuations in extent of occurrence (EOO): No
Number of Locations: 10
Continuing decline in number of locations: No
Extreme fluctuations in the number of locations: No
Lower elevation limit (metres): 400
Upper elevation limit (metres): 770
Range Map: Click here to open the map viewer and explore range.

Population [top]

Population: In 2005, the population was estimated at over 1 million individuals.
Current Population Trend: Stable
Additional data:
Number of mature individuals: 1000000 Continuing decline of mature individuals: No
Extreme fluctuations: No Population severely fragmented: No

Habitat and Ecology [top]

Habitat and Ecology: Found only in high forest from 400-770 m a.s.l., this snail is a predator specializing on small, soft-bodied invertebrates.
Systems: Terrestrial
Continuing decline in area, extent and/or quality of habitat: Yes

Threats [top]

Major Threat(s): This species is threatened by habitat degradation, caused by invasive exotic species (e.g., Cinnamomum verum) that directly impact the natural habitat.

Conservation Actions [top]

Conservation Actions: No conservation measures have been taken. Its range on Silhouette island should be protected, and invasive species should be controlled throughout the Seychelles islands. Research is needed into the species' life history and ecology.

Citation: Gerlach, J. 2009. Priodiscus serratus. The IUCN Red List of Threatened Species 2009: e.T168150A6460392. . Downloaded on 07 October 2015.
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