Coenobita cavipes(EN)

Image©Bob Hawley

Common name

Concave Land Hermit Crab.

Size

Shield length can reach 20mm.

Distribution

Taiwan, Japan(Ogasawara Islands), Philippines, Malaysia, Indonesia etc

Habitat

Mainly live in inland area.

Larval stages

Four to Five zoeal stages.

Characteristics

Adult
Body colour is brown, dark brown, gray brown with dark brown granules on the whole body.

Shield is slightly narrow with granules.

Eyestalks
Eyestalks are compressed in shape, completely black or with black colour only on the lower surfaces of the eyestalks.

Antenna
Antennal acicles are fused with the second segment of peduncle.

Antennule (1st antennal) are brown.

The bottom part of antenna are orange to red brown.

Cheliped
Left cheliped is bigger than right cheliped. No series of ridge (////) on upper outer surface of palm of left cheliped. Lower margin of palm of left cheliped with an obtuse corner in middle portion. Dactylus and fixed finger of left cheliped in white. Lower outer surface of palm with few scattered tubercles, with bluish brown patch.

Upper margins of both cheliped with brush of setae.

Merus of both cheliped transversely rugose.

Walking legs
Propodus of 3rd walking legs are relatively more slender. Inner margin of propodus of left 3rd walking leg not strongly projecting inwards and inner surface almost flat. 

Base of outer surface of dactylus of left 3rd walking leg strongly hollow.

Propodus and dactylus of right 3rd walking leg is very slim.

Outer surface of propodus of left 3rd walking leg separated from dorsal surface by a distinct well-marked longitudinal crest(B).

Abdomen
The abdomen is long.

Male coxae of 5th legs
Coxae of 5th legs of both sides thick and short, a sternal protuberance between both coxae of 5th legs large.

Juvenile
Body colour is a little bit lighter, whole body with little cream colour. There is dark gray band on the lower surfaces of the eyestalks. 

Remark

Coenobita cavipes has been confused with Coenobita violascens by some authors. For those articles mentioned Coenobita cavipes live near mangrove, it is possible that the species is Coenobita violascens instead of Coenobita cavipes which live near inland.

According to < First report of the hermit crabs Coenobita brevimanus and Coenobita rugosus (Crustacea: Decapoda: Anomura) from the Indian coast >, ”For many years Coenobita violascens has been considered as a synonym of Coenobita cavipes. However, a later report by Nakasone (1988) considered Coenobita cavipes (type locality, Japanese island of Okinawa) and Coenobita violascens (type locality, Red Sea) as distinct species, which demands further examination of Indian species of the genus Coenobita.”

In Japan, < A Report on the Distribution and Ecology of Land Hermit Crabs in Okinawa Prefecture > with clear and detail information have been already published by Nakasone (1987) to identity the different of Coenobita cavipes and Coenobita violascens and confirmed they are two different species.

In Taiwan, Foo (1989) has detail description of Coenobita cavipes in < Studies on the Hermit Crabs (Crustacea: Decapoda: Anomura) of Taiwan >.

However, according to McLaughlin P. A (2007) < A Catalog of The Hermit Crabs (Paguroidea) of Taiwan >, Coenobita violascens replaced Coenobita cavipes. It seems that McLaughlin P. A incorrectly identified the specimens of Coenobita cavipes as Coenobita violascens as image of Coenobita violascens should be Coenobita cavipes.

Below pictures are the specimens of Coenobita cavipes and Coenobita violascens I found in Taiwan. Their characteristics and habitat are same as information of Nakasone (1987).

Gallery

Reference links

  • coenobita.e-monsite.com
  • coenobitaspecies.com
  • 東京都環境局

Reference articles

  • Burggren W. W., McMahon B. R., 2009. Biology of the Land Crabs, Cambridge University Press
  • Dwi Listyo Rahayu, Hsi-Te Shih, Peter K. L. Ng, 2016. A new species of land hermit crab in the genus Coenobita Latreille, 1829 from Singapore, Malaysia and Indonesia, previously confused with C. cavipes Stimpson, 1858 (Crustacea: Decapoda: Anomura: Coenobitidae)
  • Foo-Kiat Yong, 1989. Studies on the Hermit Crabs (Crustacea: Decapoda: Anomura) of Taiwan
  • Haig J. & Ball E. E., 1988. Hermit crabs from north Australian and eastern Indonesian waters (Crustacea, Decapoda, Anomura, Paguroidea) collected during the 1975 Alpha Helix Expedition
  • Hung-Li Yuan, 2008. Morphological and Molecular Evidence for a Stepwise Terrestrial Evolution and Species Delimitation on the Coenobita Phylogeny
  • McLaughlin P. A., Komai T., Lemaitre R., Rahayu D. L., 2010. Annotated checklist of anomuran decapod crustaceans of the world (exclusive of the Kiwaoidea and families Chirostylidae and Galatheidae of the Galatheoidea) Part I. Lithodoidea, Lomisoidea and Paguroidea
  • McLaughlin P. A., Rahayu D. L., Komai T., Chan-Tin Yam, 2007. A Catalog of The Hermit Crabs (Paguroidea) of Taiwan, National Taiwan Ocean University, Keelung
  • Nakasone Y., 1988. Land hermit crabs from the Ryukyus, Japan, with a description of a new species from the Philippines (Crustacea, Decapoda, Coenobitidae)
  • Nakasone Y., 1988. Larval Stages of Coenobita purpureus Stimpson and Coenobita cavipes Stimpson Reared in the Laboratory and Survival Rates and Growth Factors of Three Land Hermit Crab Larvae (Crustacea: Anomura): Taxonomy
  • Nakasone Y., 2001. Reproductive Biology of Three Land Hennit Crabs (Decapoda: Anomura: Coenobitidae) in Okinawa, Japan
  • Reshmi R., Bijukumar A., 2010. First report of the hermit crabs Coenobita brevimanus and Coenobita rugosus (Crustacea: Decapoda: Anomura) from the Indian coast
  • Yu-Hsiang Ping and Foo-Kiat Yong, 1991. Hermit Crabs of Taiwan, SMC Publishing Inc
  • 有馬啓人, 2014. ヤドカリ (ネイチャーウォッチングガイドブック), 誠文堂新光
  • 朝倉彰, 2004. ヤドカリ類の分類学,最近の話題 - オカヤドカリ科 (Asakura A., 2004. Recent topics on taxonomy of hermit crabs from Japanese waters – family Coenobitidae)
  • 藤田喜久, 2017. 宮古諸島水納島の十脚甲殻類相 (Fujita Y., 2017. Fauna of decapod crustaceans in Minna-jima Island, Miyako Island Group, southern Ryukyu Islands, Japan)
  • 李政璋, 2015. 聖誕島與臺灣的陸蟹分類漫談, 臺灣博物 (Li Jheng Jhang, 2015. Land Crabs of Christmas Island and Taiwan, National Museum of Marine Biology and Aquarium)
  • 仲宗根幸男, 1987. 「あまん」オカヤドカリ生息実態調査報告, 沖縄教育委員会
  • 豊田幸詞, 関慎太郎, 2014. 日本の淡水性エビ.カニ: 日本産淡水性・汽水性甲殻類102種(ネイチャーウォッチングガイドブック), 誠文堂新光社

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