Gelasimus vomeris

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Two-toned fiddler crab
Scientific classification Edit this classification
Domain: Eukaryota
Kingdom: Animalia
Phylum: Arthropoda
Class: Malacostraca
Order: Decapoda
Suborder: Pleocyemata
Infraorder: Brachyura
Family: Ocypodidae
Subfamily: Gelasiminae
Genus: Gelasimus
Species:
G. vomeris
Binomial name
Gelasimus vomeris
(McNeill, 1920)
Gelasimus vomeris female
Gelasimus vomeris males fighting

Gelasimus vomeris is a species of fiddler crab found in the southwest Pacific Ocean. In Australia, it is found in the east and north from Darwin to Sydney.[1]

It is commonly known as the two-toned fiddler crab, orange-clawed fiddler crab or Southern calling fiddler crab, however the common name orange-clawed fiddler crab is also used for the fiddler crab Tubuca coarctata.[2] Previous binomial names include Uca vomeris and Uca vocans vomeris.

Description[edit]

The carapace is up to 30 mm across,[3] black-brown with blue patches to varying extent. Adult males have an enlarged claw with a grey or pink upper finger, and orange lower finger and hand.[3] Like other fiddler crabs the claw is used to scare or fight other males, and in waving displays to attract females. The lower male claw has a large triangular protection in the most distant part from the body.[4]

If caught, the colors of Gelasimus vomeris crabs will become less brilliant within minutes,[5] and in response to the presence of predators in an area, the blue color of these fiddler crabs will change over a few days to a dull muddy brown.[6]

Distribution and habitat[edit]

The preferred habitat of these crabs is unshaded sandy mud. They are found in bays, estuaries and creeks,[1] living in burrows at lower tide levels which they stay close to, typically <1 m while feeding.[7] There is a predominance of right handed individuals in colonies, one study finding left handed individuals forming only 1.4% of the study population.[8]

References[edit]

  1. ^ a b "Gelasimus Vomeris". Solitary Islands Underwater Research Group. Solitary Islands Underwater Research Group. 2022. Retrieved 2022-06-14.
  2. ^ "Gelasimus Vomeris". Fiddler Crab Info. 2022. Retrieved 2022-06-14.
  3. ^ a b "Gelasimus Vomeris". Queensland Museum. Queensland Museum. 2022. Retrieved 2022-06-14.
  4. ^ "A Revision of the Fiddler Crabs of Australia Ocypodinae (Uca)". Fiddler Crab Info. Western Australian Museum. 2022. Retrieved 2022-06-14.
  5. ^ Hemmi, J. M.; Marshall, J.; Pix, W.; Vorobyev, M.; Zeil, J. (2006). "The variable colours of the fiddler crab Uca vomeris and their relation to background and predation". The Journal of Experimental Biology. 209 (20). The Company of Biologists: 4140–4153. doi:10.1242/jeb.02483. PMID 17023607. S2CID 18350093.
  6. ^ "Crabs Change Colour to Escape Hungry Birds". Australian Broadcasting Corporation. Australian Broadcast Corporation. 2006. Retrieved 2022-06-12..
  7. ^ Ziel, J. (1998). "Homing in fiddler crabs (Uca lactea annulipes and Uca vomeris : Ocypodidae)". Journal of Comparative Physiology. 183: 367–377.
  8. ^ Backwell, P. R. Y.; Matsumasa, M.; Double, M.; Roberts, A.; Murai, M.; Keogh, J.; Jennions, M. D. (2007). "What are the consequences of being left-handed in a predominantly right-clawed fiddler crab". Proceedings of the Royal Society. 274 (1626): 2723–2729. doi:10.1098/rspb.2007.0666. PMC 2279209. PMID 17711842.

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