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Nanhaipotamon is a genus of freshwater crabs, found in southern China and Taiwan. As of 2018, 18 species have been described.[2] The genus is named after the South China Sea (Chinese:南海; Pinyin: Nánhǎi; literally: 'South Sea'), for it occurs mostly in coastal areas.

Nanhaipotamon guangdongense.jpg
Nanhaipotamon guangdongense
Scientific classification

Bott, 1968 [1]
Type species
Nanhaipotamon formosanum (Parisi, 1916)



These crabs are relatively large, with a carapace breadth of up to 50 mm. Depending on the species, the carapace may be vividly coloured, especially in males of N. hongkongense (orange to red),[3] N. aculatum (dark blue) and N. zhuhaiense (light blue).[4] Chelipeds are usually unequal, more so in larger males, where one cheliped is relatively much larger than the other. This may be of use in territorial fights, as the crabs are very aggressive towards conspecifics.[3]

Distribution and habitatEdit

Crabs of the genus Nanhaipotamon inhabit the banks of small to medium-sized hill streams, paddy fields and swamps.[2] Although not particularly a lowland species, they usually do not occur above approximately 500 meters above sea level. Most species are nocturnal, leaving their burrows at night to forage. Species belonging to this genus have been recorded from Hong Kong,[3] Macau,[5] Guangdong, Fujian, Zhejiang, Taiwan and Dongyin Island.[6]


Although crabs of the genus Nanhaipotamon are subject to the pet trade,[5] not much is known about the population status of most species,[7] and many are only known from their respective type locality. Of the 18 currently accepted species, only three have meaningful IUCN assessments, the rest all being data deficient.[8] Nearly a third of known species were described in the last ten years, and yet there is evidence that a lot more may be discovered in the near future.[7][9] Macau is one of the most densely populated places in the world, and a new species has been described there as recently as 2018.[5] The rapid urbanization of coastal regions, habitat destruction, impacts on water quality and collection for consumption and the pet trade, pose serious threats to most known species.[8][7]


Nanhaipotamon fujianense is known to be intermediate host for the lung fluke species Paragonimus skrjabini.[10]




  1. ^ Peter K. L. Ng, Danièle Guinot & Peter J. F. Davie (2008). "Systema Brachyurorum: Part I. An annotated checklist of extant Brachyuran crabs of the world" (PDF). Raffles Bulletin of Zoology. 17: 1–286. Archived from the original (PDF) on 2011-06-06.
  2. ^ a b Shih, Hsi-Te; Zhou, Xian-Min; Chen, Guo-Xiao; Chien, I-Chu; Ng, Peter K.L. (2011). "Recent vicariant and dispersal events affecting the phylogeny and biogeography of East Asian freshwater crab genus Nanhaipotamon (Decapoda: Potamidae)". Molecular Phylogenetics and Evolution. 58 (3): 427–438. doi:10.1016/j.ympev.2010.11.013.
  3. ^ a b c d Dudgeon, D.; Ng, P. K. L. (1992). "The Potmidae and Parathelphusidae (Crustacea : Decapoda : Brachyura) of Hong Kong". Invertebrate Systematics. 6 (3): 741–768. doi:10.1071/it9920741. ISSN 1447-2600.
  4. ^ a b c Ng, Peter K. L.; Huang, Jian Rong; Huang, Chao (2012-12-17). "A new species of Nanhaipotamon Bott, 1968 (Crustacea: Decapoda: Brachyura: Potamidae) from Zhuhai, Guangdong Province, China". Zootaxa. 3588 (1): 55–63. doi:10.11646/zootaxa.3588.1.2. ISSN 1175-5334.
  5. ^ a b c d e f Huang, Chao; Wong, Kai Chin; Ahyong, Shane T. (2018-12-20). "The freshwater crabs of Macau, with the description of a new species of Nanhaipotamon Bott, 1968 and the redescription of Nanhaipotamon wupingense Cheng, Yang, Zhong & Li, 2003 (Crustacea, Decapoda, Potamidae)". ZooKeys (810): 91–111. doi:10.3897/zookeys.810.30726. ISSN 1313-2970. PMC 6308228. PMID 30613174.
  6. ^ a b Shih, Hsi-Te; Chen, Guo-Xiao; Wang, Li-Min (2005-09-15). "A new species of freshwater crab (Decapoda: Brachyura: Potamidae) from Dongyin Island, Matsu, Taiwan, defined by morphological and molecular characters, with notes on its biogeography". Journal of Natural History. 39 (31): 2901–2911. doi:10.1080/00222930500214010. ISSN 0022-2933.
  7. ^ a b c Hui, Tommy Chung Hong; Leven, Michael Robertson; Stanton, David John (2018-01-26). "Distribution of Nanhaipotamon hongkongense (Shen, 1940) (Crustacea: Brachyura: Potamidae), a freshwater crab endemic to Hong Kong". Journal of Threatened Taxa. 10 (1): 11156–11165. doi:10.11609/jott.3619.10.1.11156-11165. ISSN 0974-7907.
  8. ^ a b "The IUCN Red List of Threatened Species". IUCN Red List of Threatened Species. Retrieved 2019-05-20.
  9. ^ Huang, Chao; Mao, Si Ying (2014-02-12). "Two new potamid crabs, Yuexipotamon arcophallus new genus, new species and Minutomon shanweiense new genus, new species, (Crustacea: Decapoda: Brachyura: Potamidae) from southern China". Zootaxa. 3764 (4): 455. doi:10.11646/zootaxa.3764.4.5. ISSN 1175-5334.
  10. ^ a b Lin, Guo-Hua; Cheng, You-Zhu; Chen, Shao-Hong (February 2013). "[A new species of the genus Nanhaipotamon (Decapoda:Potamidae) serving as intermediate host of Paragonimus skrjabini]". Zhongguo Ji Sheng Chong Xue Yu Ji Sheng Chong Bing Za Zhi = Chinese Journal of Parasitology & Parasitic Diseases. 31 (1): 39–42. ISSN 1000-7423. PMID 24812835.
  11. ^ a b c d e f g h i j "A revision of freshwater crabs of the genus nanhaipotamon bott, 1968 from China (Crustacea: Decapoda: Brachyura: Potamidae)". ResearchGate. Retrieved 2019-05-17.
  12. ^ Lin, Guo-Hua; Cheng, You-Zhu; Chen, Shao-Hong (2012-12-30). "[A new species of the genus Nanhaipotamon (Decapoda: Potamidae) from China]". Zhongguo Ji Sheng Chong Xue Yu Ji Sheng Chong Bing Za Zhi = Chinese Journal of Parasitology & Parasitic Diseases. 30 (6): 434–437. ISSN 1000-7423. PMID 23484252.
  13. ^ Cheng, You-Zhu; Li, Li-Sa; Zhang, Yi (August 2009). "[A new species of the genus Nanhaipotamon (Decapoda: Potamidae) from Xiapu County, Fujian]". Zhongguo Ji Sheng Chong Xue Yu Ji Sheng Chong Bing Za Zhi = Chinese Journal of Parasitology & Parasitic Diseases. 27 (4): 368–369. ISSN 1000-7423. PMID 20067001.