A nut crab (Ebalia granulosa)

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



Ebalia granulosa has a carapace about 9.5 mm long up to a maximum of 11 mm, and it is a yellowish colour with 2 red spots. The carapace is as broad as it is long and lateral (branchial) regions have surface swellings, which are smaller than those of Ebalia tumefacta. The posterior region of the carapace has an indent, with a more sharply pronounced V indent in the males. The claws are of equal length and stout, with sharp longitudinal ridges on fifth segment (carpus) and fourth segment (merus). The other legs bear stout spines.

Recorded distribution in Britain and Ireland

Recorded off east Scotland in the Firth of Forth, west Scotland in the Sound of Arisaig, Galway Bay, Ireland, and at three sites in Salcombe Harbour, Devon, England.

Global distribution

Found from the British Isles south to Spain and the Mediterranean.


Ebalia granulosa can be found on coarse grounds, from the shallow sublittoral to beyond the edge of the continental shelf.

Depth range


Identifying features

  • Carapace as broad as long with a maximum length of 11 mm.
  • Carapace yellowish with 2 red spots and branchial swellings.
  • Posterior margin of carapace has shallow V indent in females, more sharply indented in males.
  • Claws (chelipeds) of equal length but proportionally larger than in other nut crab species.
  • Claws have sharp longitudinal ridges on fifth and fourth segments.
  • Female claws shorter than in males and the sixth segment (propodus) is less swollen.

Additional information

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Listed by

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  1. Hayward, P., Nelson-Smith, T. & Shields, C. 1996. Collins pocket guide. Sea shore of Britain and northern Europe. London: HarperCollins.

  2. Hayward, P.J. & Ryland, J.S. 1994. The marine fauna of the British Isles and north-west Europe. Volume 1. Introduction and Protozoans to Arthropods. Oxford: Clarendon Press.

  3. Howson, C.M. & Picton, B.E., 1997. The species directory of the marine fauna and flora of the British Isles and surrounding seas. Belfast: Ulster Museum. [Ulster Museum publication, no. 276.]

  4. Ingle, R., 1993. Hermit crabs of the northeastern Atlantic Ocean and the Mediterranean Sea. An illustrated key. London: Natural History Museum Publications, Chapman & Hall.

  5. Ingle, R.W., 1980. British Crabs. Oxford: British Museum (Natural History), Oxford University Press.

  6. Ingle, R.W., 1983. Shallow-water Crabs. Cambridge: Cambridge University Press.[Synopses of the British Fauna No. 25].


  1. NBN (National Biodiversity Network) Atlas. Available from: https://www.nbnatlas.org.

  2. OBIS (Ocean Biodiversity Information System),  2024. Global map of species distribution using gridded data. Available from: Ocean Biogeographic Information System. www.iobis.org. Accessed: 2024-06-15


This review can be cited as:

Neish, A.H. 2003. Ebalia granulosa A nut 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 15-06-2024]. Available from: https://www.marlin.ac.uk/species/detail/1906

Last Updated: 28/05/2003