information on the biology of species and the ecology of habitats found around the coasts and seas of the British Isles

Bristly crab (Pilumnus hirtellus)

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



Carapace broader than it is long (up to 3 cm across), with 5 sharp unequally sized antero-lateral teeth on each side. Frontal region very finely serrated between the eyes. Carapace and all walking legs densely covered with club-shaped setae. Chelipeds stout and robust, one (usually the right) much larger than other, and brownish or purple in colour with orange to cream inner surfaces. Carapace reddish-brown, sometimes purplish in colour. Walking legs with alternate bands of purple and white or grey.

Recorded distribution in Britain and Ireland

Found on all British coasts but is most frequent in the south and west.

Global distribution

From southern Norway southwards to Cape Verde Islands, Mediterranean and Black Sea.


Found on various substrata from muddy sand to rocks, under stones and sometimes among seaweed holdfasts, from the lower shore to depths of up to 80 m.

Depth range


Identifying features

  • 1st and 2nd antero-lateral teeth smaller than the rest.
  • Fixed finger of chelae brown at tip.
  • Dactyls curved distally and acutely pointed.
  • Propodus of smaller chela always spiny, that of larger one smooth or with just a few tubercles.
  • Carpus of walking legs may have small spine on the distal upper margin.

Additional information

Dorsal surface of carapace bears short spines beneath the setae; clearly evident in young specimens but increasingly hidden by hairs in older crabs. Silt often accumulates among setae making Pilumnus hirtellus difficult to see on dark or silty surfaces.

Listed by

- none -

Further information sources

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  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. Fish, J.D. & Fish, S., 1996. A student's guide to the seashore. Cambridge: Cambridge University Press.

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

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

  5. Hiscock, K., Southward, A., Tittley, I., Jory, A. & Hawkins, S., 2001. The impact of climate change on subtidal and intertidal benthic species in Scotland. Scottish National Heritage Research, Survey and Monitoring Report , no. 182., Edinburgh: Scottish National Heritage

  6. 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.]

  7. Ingle, R., 1997. Crayfishes, lobsters and crabs of Europe. An illustrated guide to common and traded species. London: Chapman and Hall.

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


This review can be cited as:

Skewes, M. 2008. Pilumnus hirtellus Bristly crab. In Tyler-Walters H. and Hiscock K. (eds) Marine Life Information Network: Biology and Sensitivity Key Information Reviews, [on-line]. Plymouth: Marine Biological Association of the United Kingdom. [cited 22-09-2018]. Available from:

Last Updated: 08/05/2008