Johora singaporensis 

Scope: Global
Language: English

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Taxonomy [top]

Kingdom Phylum Class Order Family
Animalia Arthropoda Malacostraca Decapoda Potamidae

Scientific Name: Johora singaporensis Ng, 1986
Common Name(s):
English Singapore Freshwater Crab
Taxonomic Notes: Subfamily Potamiscinae.

Assessment Information [top]

Red List Category & Criteria: Critically Endangered B1ab(iii)+2ab(iii) ver 3.1
Year Published: 2008
Date Assessed: 2008-01-01
Assessor(s): Esser, L.J., Cumberlidge, N. & Yeo, D.
Reviewer(s): Cumberlidge, N. & McIvor, A.
Listed as Critically Endangered. Previously known from two locations, one which was in Bukit Timah Nature Reserve and the other outside the reserve. There have been intensive surveys within the reserve and the species has not been found, implying that it has been extirpated from this location. The suspected cause of this is acidification of water. Therefore now only found in one location in a drainage which runs through private property and partly through military land. However recent development of this land has lowered the water table and so this second population is under severe threat and there is likely to be a decline in habitat availability and quality. It is a small streamlet, so extent of occurrence is likely to be less than 100 km² and area of occupancy less than 10 km².

Geographic Range [top]

Range Description:Singapore: Known only from Bukit Timah Nature Reserve (no longer found here) and a very small population in a streamlet on a small hill near Bukit Batok. The species is endemic to Singapore.
Countries occurrence:
Additional data:
Number of Locations:1
Range Map:Click here to open the map viewer and explore range.

Population [top]

Population:Known only from a very small population in a streamlet on a small hill near Bukit Batok in the Bukit Timah Nature Reserve.
Current Population Trend:Unknown
Additional data:
Population severely fragmented:No

Habitat and Ecology [top]

Habitat and Ecology:This species is found under rocks at the sides of the main stream as well as hiding inside clumps of leaves and detritus, even in almost stagnant pools. It feeds on plant detritus as well as on oligochaete worms, which are present in the soft mud of a stream. Quite terrestrial habits and mainly nocturnal species (Ng 1988). Undisturbed primary hill forest streams.

Threats [top]

Major Threat(s): Loss of forest cover and aquatic pollution. Acidification of water and lowering of water table, probably reducing stream flow and availability of suitable habitats.

Conservation Actions [top]

Conservation Actions: The continued conservation of Bukit Timah Hill and the associated stream systems in Jungle Fall Valley offers the only hope for survival of this species in Singapore.

Errata [top]

Errata reason: This errata version of the 2008 assessment was created to correct the formatting used for the Assessor names (and hence the assessment citation) and Reviewer names.

Citation: Esser, L.J., Cumberlidge, N. & Yeo, D. 2008. Johora singaporensis (errata version published in 2017). The IUCN Red List of Threatened Species 2008: e.T134219A114582053. . Downloaded on 20 September 2018.
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