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Geosesarma nemesis Ng, 1986
| Family Name: | Sesarmidae |
| Taxonomic Group: | Invertebrates (Crustacean, Crab and Prawn) |
| Common Name: | Little Land Crab |
Name
Description
| Description | Carapace varies from reddish-brown to bright red for large males. |
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Ecology, Habitat & Location
| Ecological Notes | Semi-terrestrial habits. Digs shallow burrows under rocks and vegetation next to small freshwater streams in well-shaded forests. Primarily herbivorous. |
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| Habitats | Forest, Freshwater |
| Distribution | In Singapore, found mainly in Bukit Timah Nature Reserve and in one or two streams in the Bukit Gombak area. Also occurs in southern Malaysia. |
| Nature Reserves | Bukit Timah Nature Reserve |
Conservation
| Trends & Threats | Forest clearance and water pollution. The species used to be common in forested areas next to Bukit Timah Hill but the only intact populations now live on the reserve, and surprisingly, in one or two small streams on opposite side of Bukit Timah Road in the Bukit Gombak area. Most other peripheral populations have been exterminated by wanton use of insecticides. Insecticides, supposedly used to exterminate breeding mosquito larvae, are indiscriminately sprayed even on flowing streams and clean waters with small fishes where mosquito larvae are absent, are very destructive to freshwater life, and will exterminate whole communities and ecosystems. |
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| Scientific Interest & Potential Value | This species was first described from Bukit Timah Hill in Singapore only in 1986 after having long been was mistaken for another species, G. ocypoda, originally described from Sumatra. Supposedly a highland species that is replaced in lowland by another Geosesarma species, G. perracae (Nobili, 1903); the two species, however, can be found living together instead in Singapore, probably due to the high degree of disturbance of the natural habitat here. The second species is regarded as vulnerable as it has a wider range. |
| Conservation Notes | Conservation of good primary and late secondary forests. Properly and carefully planned and thought out use of insecticides and other anti-mosquito measures. |
Status
| Species Status | Native |
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| Singapore Red Data Book Status | Endangered (EN) [2008], Endangered (E) [1994] |
Photos
References
| References | Davison, G.W.H., Ng, P.K.L. & Ho, H.C (Eds.). 2008. The Singapore Red Data Book (2nd Edition). Singapore: Nature Society (Singapore). 285pp Ng, P.K.L. 1988. The freshwater crabs of Peninsular Malaysia and Singapore. Singapore: Department of Zoology, NUS. 156pp |
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