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

Sea bristletail (Petrobius maritimus)

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



Petrobius maritimus are fast-running insects with elongate, tapered, grey mottled coloured bodies up to 1.5 cm long. They have three pairs of legs and a triple forked tail. Individuals have prominent eyes and a short pair of palps on the head set between a further pair of long, bristly antennae of 30 or more segments.

Recorded distribution in Britain and Ireland

Recorded around the coast of Britain but with an absence of records from north east Scotland and the south east of England. No records were found for Ireland. However, this species is likely to be under-recorded.

Global distribution

Common throughout the north east Atlantic region.


Found above high water, usually under stones and on screes or in chinks of rock and wood. Occurs inland in several places along the west coast of Britain.

Depth range


Identifying features

  • Elongate, tapered body, up to 1.5 cm.
  • Grey coloured body.
  • Triple forked tail.
  • Long, bristly antennae of 30 or more segments.
  • Prominent eyes.

Additional information

Petrobius maritimus, may be confused with Petrobius brevistylis which occurs in the same habitat. The two species can be separated by the sub-coxae of the male. In Petrobius brevistylis the 8th abdominal segment is prolonged into rounded lobes, whereas lobes are absent in Petrobius maritimus.

Listed by

- none -

Further information sources

Search on:


  1. Cheng, L. (ed.), 1976. Marine insects. Amsterdam: North-Holland Publishing Company.

  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. 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.]

  6. JNCC (Joint Nature Conservation Committee), 1999. Marine Environment Resource Mapping And Information Database (MERMAID): Marine Nature Conservation Review Survey Database. [on-line]

  7. National Biodiversity Network (NBN) Atlas website. Available from:  Accessed 01 April 2017

  8. Ruppert, E.E. & Barnes, R.D., 1994. Invertebrate zoology (6th ed.). Fort Worth, USA: Saunders College Publishing.


This review can be cited as:

Ballerstedt, S. 2008. Petrobius maritimus Sea bristletail. 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 26-09-2018]. Available from:

Last Updated: 03/06/2008