Helice tridens

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Helice tridens
Helice tridens (Kohnoura).jpg
Scientific classification
Kingdom: Animalia
Phylum: Arthropoda
Subphylum: Crustacea
Class: Malacostraca
Order: Decapoda
Infraorder: Brachyura
Family: Varunidae
Genus: Helice
Species: H. tridens
Binomial name
Helice tridens
(De Haan, 1835) [1]
Synonyms [2]
  • Ocypode tridens De Haan, 1835
  • Cyclograpsus latreillii H. Milne-Edwards, 1837
  • Helice latreillei H. Milne-Edwards, 1837

Helice tridens is a species of crab which lives on mudflats around the coasts of Japan and the Korean Peninsula.[3]


It is semi-terrestrial, returning to the sea to spawn.[4] The species appears to be adversely affected by the presence of raccoons (Procyon lotor), an invasive predator.[4] H. tridens has a salinity requirement which lies between those of two other estuarine crabs in Japan, Helicana japonica and Chiromantes dehaani.[5]

Smaller individuals shelter in burrows in reed marshes, apparently in order to avoid cannibalism; this may also be the reason for the migration of larger individuals to brackish water lagoons in summer, when the crabs exceed their carrying capacity.[6]


Helice tridens was first described by Wilhem de Haan in an 1835 volume of Fauna Japonica, as Ocypode tridens.[7] The former subspecies H. t. wuana and H. t. sheni are now recognised as a separate species, Helicana wuana.[2]


  1. ^ "Helice tridens". Crabs of Japan. Retrieved January 31, 2009. 
  2. ^ a b P. K. L. Ng, D. Guinot & P. J. F. Davie (2008). "Systema Brachyurorum: Part I. An annotated checklist of extant Brachyuran crabs of the world". Raffles Bulletin of Zoology 17: 1–286. 
  3. ^ Hsi-Te Shih and Hiroshi Suzuki (2008). "Taxonomy, phylogeny, and biogeography of the endemic mudflat crab Helice/Chasmagnathus complex (Crustacea: Brachyura: Varunidae) from East Asia" (PDF). Zoological Studies 47 (1): 114–125. 
  4. ^ a b Hisayo Hayama, Masato Kaneda & Mayuh Tabata (2006). "Rapid range expansion of the feral raccoon (Procyon lotor) in Kanagawa Prefecture, Japan, and its impact on native organisms". In F. Koike, M. N. Clout, M. Kawamichi, M. De Poorter & K. Iwatsuki. Assessment and Control of Biological Invasion Risks. Shoukadoh Book Sellers, Kyoto, Japan and IUCN, Gland, Switzerland. pp. 196–199. 
  5. ^ Bambang Irawan & Akihiro Kijima (1994). "Difference of salinity requirements among the three estuarine crab species, Chiromantes dehaani, Helice tridens and H. japonica (Brachyura: Grapsidae)". Tohoku Journal of Agricultural Research 44 (1-4). 
  6. ^ Yasushi Kurihara, Katsuhiro Sekimoto & Masahide Miyata (1988). "Wandering behaviour of the mud-crab Helice tridens related to evasion of cannibalism". Marine Ecology Progress Series 49: 41–50. doi:10.3354/meps049041. 
  7. ^ Wilhem de Haan (1835). "Ocypode (Helice) tridens sp. nov.". In Philipp Franz von Siebold. Fauna Japonica. p. 57. 

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