MarLIN

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

A sipunculid worm (Nephasoma (Nephasoma) minutum)

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

Summary

Description

Nephasoma minutum, like all sipunculid worms, has an unsegmented body consisting of an introvert and a trunk. The introvert can be withdrawn into the trunk. The mouth, which is on the end of the introvert, is surrounded by up to 16 tentacles. The trunk is at least three times as long as it is wide and about the same length of the introvert. The introvert is covered by many spine-like hooks at the anterior end. Nephasoma minutum may reach up to 1.5 cm in length. It is very variable in colour, from grey-yellow to orange or pure white. The oral tentacles of Nephasoma minutum are largely rudimentary and the introvert hooks are arranged irregularly. The oral disc has two distinct lobes.

Recorded distribution in Britain and Ireland

Found throughout the British Isles and off north-east Ireland.

Global distribution

-

Habitat

Nephasoma minutum is a benthic species often found in rock crevices on the lower shore or sublittorally but may also occur in mud, sand or gravel.

Depth range

-

Identifying features

  • Up to 1.5 cm in length.
  • Trunk without shields.
  • Tentacles entirely surround the mouth but are rudimentary.
  • Dorsal pair of retractor muscles are absent.
  • Two internal kidney-like organs (nephridia).
  • Nephridiopores posterior to anus.

Additional information

Unlike Nephasoma rimicola, Nephasoma minutum has only rudimentary oral tentacles the introvert hooks are arranged irregularly and the oral disc has two distinct lobes (Cutler, 1994).

Listed by

- none -

Further information sources

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Bibliography

  1. Cutler, E.B., 1994. The Sipuncula. Their systematics, biology and evolution. Ithaca, Cornell University Press.

  2. Gibbs, P.E., 1986. The taxonomy of some little-known Sipuncula from the North-East Atlantic region including new records. Journal of the Marine Biological Association of the United Kingdom, 66, 335-341

  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. National Biodiversity Network (NBN) Atlas website. Available from: http://www.nbnatlas.org.  Accessed 01 April 2017

  6. OBIS,  2017. Global map of species distribution using gridded data. Available from: Ocean Biogeographic Information System. www.iobis.org. Accessed: 2017-11-20

  7. Stephen, A.C. & Edmonds, S.J., 1972. The Phyla Sipuncula and Echiura. London, Trustees of the British Museum (Natural History).

Citation

This review can be cited as:

Barnes, M.K.S. 2008. Nephasoma (Nephasoma) minutum A sipunculid worm. 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. Available from: http://www.marlin.ac.uk/species/detail/119

Last Updated: 22/05/2008