Ozius deplanatus

Black finger crab
Scientific classification
Kingdom: Animalia
Phylum: Arthropoda
Class: Malacostraca
Order: Decapoda
Suborder: Pleocyemata
Infraorder: Brachyura
Family: Oziidae
Genus: Ozius
Species:
O. deplanatus
Binomial name
Ozius deplanatus
(White, 1847)[1]
Synonyms[1]

Xantho deplanatus White, 1847

Ozius deplanatus, commonly known as the black finger crab and the iron crab, is a species of crab found in New Zealand and Australia.[2][3]

Distribution

It is common around the North Island of New Zealand.[2] Found in Australia from Eastern Victoria to New South Wales, on Flinders Island and the Kent Group.[3][4] It is also found on Lord Howe Island and Norfolk Island.[4]

Habitat

O. deplanatus is found under boulders and among stones in the lower to mid tidal regions of the intertidal zone on sheltered rocky and gravel shores.[2][5][6]

It is distributed sparsely, with one individual per 5 m2.[2]

Description

Adults average 57 mm (2.2 in) in size with a flattened oval-shaped carapace that is wide in the front with blunt lobed edges. This can be a rusty red to chocolate brown colour with light mottling. Underside may be a paler cream colour.[3] The antennae are dark red to brown. Claws are large with a smooth texture.[3] Fingers may be black or brown in colour.[2] Walking legs are pale red with golden setae or hairs.[2]

Behaviour and diet

The black finger crab is a scavenger.[6] It feeds on snails, half-crabs and hermit crabs. It is known to chip away at the shells of larger snails before grasping the animal with its mouth-parts. Smaller snails are crushed by the crab's large claws. It also feeds on limpets and chitons by using the tip of its claw to remove them from a rock.[2]

It will spread its claws when started or threatened.[2]

References

  1. ^ a b "Ozius deplanatus (White, 1847)". DecaNet. World Register of Marine Species. 2025. Retrieved 17 December 2025.
  2. ^ a b c d e f g h Carson, Sally; Morris, Rod (2017). Collins Field Guide to the New Zealand Seashore. Harper Collins Publishers (New Zealand). ISBN 978-1-7755-4010-6.
  3. ^ a b c d Wilkens, Serena; Ahyong, Shane (2015). Coastal Crabs: a Guide to the Crabs of New Zealand (PDF). NIWA Taihoro Nukurangi.
  4. ^ a b Edgar, Graham. (2012). Australian marine life : the plants and animals of temperate waters. Reed New Holland. ISBN 9781921517174. OCLC 793720774.
  5. ^ Bennett, Edward William (1964). The marine fauna of New Zealand: Crustacea Brachyura. RE Owen, Government Printer.
  6. ^ a b "Crab, Black Fingered". www.marinelife.ac.nz. Retrieved 2019-09-29.