A sea cucumber (Labidoplax media)

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



A small worm-like sea cucumber, 2 -4 cm in length, lacking tube feet or respiratory trees. The body wall is transparent but bears small brown glandular papillae. Five prominent opaque bands (the longitudinal muscles) are visible through the transparent body wall. The mouth is surrounded by 12 tentacles, of similar size, each bearing four digits. Gonads consist of two simple branched tubules in the coelum.

Recorded distribution in Britain and Ireland

Recorded from the Quoile estuary in Strangford Lough, Northern Ireland and from similar sheltered habitats in the sea lochs of western Scotland.

Global distribution

Originally described from Bergen, Norway. Recently recorded from the Adriatic in the Mediterranean. No other records found.


Lives near the surface or just buried in soft, fine glutinous mud in shallow, extremely sheltered conditions, such as the sheltered basins of lagoons and sea lochs.

Depth range


Identifying features

  • Tube feet and respiratory trees absent.
  • Anchor and anchor plate spicules only present (no wheel or sigmoid spicules found).
  • Anchor plates regular in shape and narrowed into a distinct handle forming a racket shape.
  • 12 digitate tentacles, each with four digits.
  • Small, 2-4cm in length.
  • Gonadial tubules branched.

Additional information

Labidoplax media may be synonymous with Labidoplax buskii (Ostergren, 1905) (Howson & Picton, 1999). Gotto & Gotto (1972) stated that Labidoplax media can be distinguished from Labidoplax buskii by the presence of 12 tentacles (rather than 11), four tentacular digits (rather than 5) and the branched gonadial tubules. A full description of Labidoplax media is provided by Gotto & Gotto (1972) and keys to synaptids by Clark (1907) and Mortensen (1927).


  1. Clark, H.L., 1907. The apodous holothurians. A monograph of the Synaptidae and Molpadiidae, including a report on the representatives of these families in the collections of the United States National Museum. Washington: Smithsonian Institute. [Smithsonian Contributions to Knowledge, no. 1723, part of volume 35.]

  2. Gotto, D.M. & Gotto, R.V., 1972. Labidoplax media Oestergren: a sea-cucumber new to British and Irish waters, with observational notes. Irish Naturalists' Journal, 17, 250-252.

  3. Howson, C.M. & Picton, B.E. ed., 1999. The species directory of the marine fauna and flora of the British Isles and surrounding seas. CD-ROM Edition. Ulster Museum and The Marine Conservation Society, Belfast and Ross-on-Wye., Belfast: Ulster Museum. [Ulster Museum publication no. 280.]

  4. Hyman, L.V., 1955. The Invertebrates: Vol. IV. Echinodermata. The coelomate Bilateria. New York: McGraw Hill.

  5. Mortensen, T.H., 1927. Handbook of the echinoderms of the British Isles. London: Humphrey Milford, Oxford University Press.

  6. Nichols, D., 1969. Echinoderms (4th ed.). London: Hutchinson & Co.

  7. Salvini-Plawen, L.V., 1977. Caudofoveata (Mollusca), Priapulida and apodous holothurian (Labidoplax, Myriothrochus) off Banyuls and throughout the Mediterranean. Vie et Milieu, Paris, 27, 55-81.

  8. Smirnov, A.V., 1998. On the classification of the apodid holothurians. In Proceedings of the ninth international echinoderm conference, San Francisco, California, USA, 5-9 August 1996. Echinoderms: San Francisco, (ed. R. Mooi & M. Telford), pp. 517-522. Rotterdam: A.A. Balkema.


  1. Centre for Environmental Data and Recording, 2018. Ulster Museum Marine Surveys of Northern Ireland Coastal Waters. Occurrence dataset https://www.nmni.com/CEDaR/CEDaR-Centre-for-Environmental-Data-and-Recording.aspx accessed via NBNAtlas.org on 2018-09-25.

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

  3. OBIS (Ocean Biodiversity Information System),  2024. Global map of species distribution using gridded data. Available from: Ocean Biogeographic Information System. www.iobis.org. Accessed: 2024-05-20


This review can be cited as:

Tyler-Walters, H., 2005. Labidoplax media A sea cucumber. 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 20-05-2024]. Available from: https://www.marlin.ac.uk/species/detail/1557

Last Updated: 02/06/2005