Arch-fronted swimming crab (Liocarcinus navigator)

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



The carapace of Liocarcinus arcuatus is as long as it is broad (up to 30 mm in length and 30 mm in breadth), with 5 sharp teeth posterior to the eyes on each side. The frontal margin between the eyes is hairy and without teeth. The carapace is gently convex with minute transverse ridges. It is brown in colour and the limbs are somewhat paler.

Recorded distribution in Britain and Ireland

Liocarcinus arcuatus is a southerly species found on south and west coasts of the British Isles, and at Flamborough Head.

Global distribution



Found on mixed sandy substrata from the shallow sublittoral to offshore (2-108 m).

Depth range


Identifying features

  • The 5 anterolateral teeth on the carapace are very unequal, with the 3rd and 5th being larger than the others.
  • The dactyls of the 5th walking legs are sharply pointed and fringed with hairs on both sides.

Additional information

No text entered

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

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

  4. 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.]

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


  1. Centre for Environmental Data and Recording, 2018. Ulster Museum Marine Surveys of Northern Ireland Coastal Waters. 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. NBN (National Biodiversity Network) Atlas. Available from:

  5. OBIS (Ocean Biodiversity Information System),  2024. Global map of species distribution using gridded data. Available from: Ocean Biogeographic Information System. Accessed: 2024-06-25


This review can be cited as:

Skewes, M. 2005. Liocarcinus navigator Arch-fronted swimming 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 25-06-2024]. Available from:

Last Updated: 17/11/2005