Common spider crab (Maja brachydactyla)

Distribution data supplied by the Ocean Biodiversity Information System (OBIS). To interrogate UK data visit the NBN Atlas.Map Help



The largest spider crab in the British Isles. The common spider crab is red, brownish-red, or yellowish in colour and the body is up to 20 cm long. It has a circular to oval shell (carapace), broad at the back and narrow at the front. Strong tapering spines border the shell, while the rest of the shell bears smaller spines. The small eyes are either side of two distinct frontal spines. The legs are covered by hairs. The first pair of legs bear small claws while the rest taper to stout, dark tips. The shell is usually covered with algae.

Recorded distribution in Britain and Ireland

Found in south and west Britain and Ireland, this species is thought to be extending its range further North in scotland.

Global distribution



Found at extreme low water to around 50 m, Maja brachydactyla inhabitats rocky or coarse sandy areas.

Depth range


Identifying features

  • Carapace strongly convex, both transversely and longitudinally.
  • Dorsal surface with many short and acute spines.
  • Frontal region produced as a stout, short, bifid rostrum each half conspicuously diverging outward or almost parallel.
  • Chelipeds equal and along with second to fifth pairs of pereiopods, moderately stout, segments with spinules.

Additional information

Maja brachydactyla was until recently considered to be conspecific with Maja squinado. Maja squinado has a Mediterranean distribution, while Maja brachydactyla is found in the northeast Atlantic Ocean from Morrocco to Scotland.

Listed by

- none -


  1. Crothers, J. & Crothers, M., 1988. A key to the crabs and crab-like animals of British inshore waters. Somerset, England: Field Studies Council. [AIDGAP guide, no. 155.]

  2. Hayward, P.J. & Ryland, J.S. (ed.) 1995b. Handbook of the marine fauna of North-West Europe. Oxford: Oxford University Press.

  3. Neumann, V. 1998. A review of the Maja squinado (Crustacea: Decapoda: Brachyura) species-complex with a key to the eastern Atlantic and Mediterranean species of the genus Journal of Natural History, 32, 1667-1684


  1. Cofnod – North Wales Environmental Information Service, 2018. Miscellaneous records held on the Cofnod database. Occurrence dataset: accessed via on 2018-09-25.

  2. Environmental Records Information Centre North East, 2018. ERIC NE Combined dataset to 2017. Occurrence dataset: accessed via on 2018-09-38

  3. Fenwick, 2018. Aphotomarine. Occurrence dataset Accessed via on 2018-10-01

  4. Isle of Wight Local Records Centre, 2017. IOW Natural History & Archaeological Society Marine Invertebrate Records 1853- 2011. Occurrence dataset: accessed via on 2018-09-27.

  5. Kent Wildlife Trust, 2018. Kent Wildlife Trust Shoresearch Intertidal Survey 2004 onwards. Occurrence dataset: accessed via on 2018-10-01.

  6. Manx Biological Recording Partnership, 2018. Isle of Man historical wildlife records 1990 to 1994. Occurrence dataset: accessed via on 2018-10-01.

  7. National Trust, 2017. National Trust Species Records. Occurrence dataset: accessed via on 2018-10-01.

  8. Nature Locator, 2017. Sealife Tracker. Occurrence dataset: accessed via on 2018-10-01.

  9. NBN (National Biodiversity Network) Atlas. Available from:

  10. OBIS (Ocean Biodiversity Information System),  2024. Global map of species distribution using gridded data. Available from: Ocean Biogeographic Information System. Accessed: 2024-06-12

  11. Outer Hebrides Biological Recording, 2018. Invertebrates (except insects), Outer Hebrides. Occurrence dataset: accessed via on 2018-10-01.

  12. South East Wales Biodiversity Records Centre, 2018. SEWBReC Myriapods, Isopods, and allied species (South East Wales). Occurrence dataset: accessed via on 2018-10-02.


This review can be cited as:

Hosie, A.M. 2009. Maja brachydactyla Common spider crab. In Tyler-Walters H. and Hiscock K. Marine Life Information Network: Biology and Sensitivity Key Information Reviews, [on-line]. Plymouth: Marine Biological Association of the United Kingdom. [cited 12-06-2024]. Available from:

Last Updated: 09/01/2009