The Marine Life Information Network

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


Spotted cowrie (Trivia monacha)

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



This species has a thickly calcified, glossy shell, with closely spaced transverse ridges. The shell is up to 12 mm long by 8mm wide. The upper surface is reddish-brown in colour with 3 diagnostic spots.The underside of the shell is flattened and white. The head, tentacles, foot and mantle are brightly coloured, from yellow, red, orange and brown, the foot often being paler. When the animal is active the mantle almost completely obscures the shell, and the mantle edge draws out anteriorly into a long siphon. The shell aperture is narrow, running the whole length of the shell, turned left at the ends with both sides ridged.

Recorded distribution in Britain and Ireland

This species is widely distributed, mainly around the west coast of Britain and Ireland.

Global distribution



Trivia monacha is found on the lower shore and sublittorally on rocky coasts associated with its prey, colonial sea squirts.

Depth range


Identifying features

  • Oval, glossy shell with marked ridges on surface.
  • Shell up to 12 mm x 8 mm.
  • Long , narrow aperture.
  • Upper shell surface is reddish-brown with 3 brown spots.
  • Underside of shell is flattened and white.
  • Mantle wraps around almost entire shell when animal is active.
  • Head, tentacles, foot and mantle brightly coloured from yellow, red, orange and brown.

Additional information

Trivia monacha can be confused with Trivia arctica, the former being larger and having 3 distinctive brown spots on its shell. There is no operculum present, and the females have an additional ventral pedal gland. This species feeds on the ascidians Botryllus schlosseri, Botrylloides leachi, and Diplosoma listerianum. Breeding occurs in late spring and summer. The female deposits flask-shaped egg capsules (each containing 800 eggs), in holes that have been eaten out of the ascidian. After a few weeks the larva emerge and are free swimmming for a few months. Juveniles (5 mm long) have a short spire, wide aperture and lack the characteristic ridging of mature adults.

Listed by

- none -


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

  2. Gibson, R., Hextall, B. & Rogers, A., 2001. Photographic guide to the sea and seashore life of Britain and north-west Europe. Oxford: Oxford University Press.

  3. Graham, A., 1988. Molluscs: prosobranchs and pyramellid gastropods (2nd ed.). Leiden: E.J. Brill/Dr W. Backhuys. [Synopses of the British Fauna No. 2]

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

  5. Hayward, P.J. & Ryland, J.S. (ed.), 1995. The marine fauna of the British Isles and north-west Europe. Volume 2. Molluscs to Chordates. Oxford Science Publications. Oxford: Clarendon Press.

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

  8. Naylor, P., 2000. Marine Animals of the South West. Plymouth: Sound Diving Publications

  9. Picton, B.E. & Costello, M.J., 1998. BioMar biotope viewer: a guide to marine habitats, fauna and flora of Britain and Ireland. [CD-ROM] Environmental Sciences Unit, Trinity College, Dublin.

  10. Seaward, D.R., 1982. Sea area atlas of the marine molluscs of Britain and Ireland. Peterborough: Nature Conservancy Council.


  1. Centre for Environmental Data and Recording, 2018. IBIS Project Data. Occurrence dataset: accessed via on 2018-09-25.

  2. Centre for Environmental Data and Recording, 2018. Ulster Museum Marine Surveys of Northern Ireland Coastal Waters. Occurrence dataset accessed via on 2018-09-25.

  3. Cofnod – North Wales Environmental Information Service, 2018. Miscellaneous records held on the Cofnod database. Occurrence dataset: accessed via on 2018-09-25.

  4. Conchological Society of Great Britain & Ireland, 2018. Mollusc (marine) data for Great Britain and Ireland - restricted access. Occurrence dataset: accessed via on 2018-09-25.

  5. Conchological Society of Great Britain & Ireland, 2018. Mollusc (marine) records for Great Britain and Ireland. Occurrence dataset: accessed via on 2018-09-25.

  6. Environmental Records Information Centre North East, 2018. ERIC NE Combined dataset to 2017. Occurrence dataset: accessed via on 2018-09-38

  7. Fenwick, 2018. Aphotomarine. Occurrence dataset Accessed via on 2018-10-01

  8. Fife Nature Records Centre, 2018. St Andrews BioBlitz 2015. Occurrence dataset: accessed via on 2018-09-27.

  9. Kent Wildlife Trust, 2018. Kent Wildlife Trust Shoresearch Intertidal Survey 2004 onwards. Occurrence dataset: accessed via on 2018-10-01.

  10. Manx Biological Recording Partnership, 2017. Isle of Man wildlife records from 01/01/2000 to 13/02/2017. Occurrence dataset: accessed via on 2018-10-01.

  11. Manx Biological Recording Partnership, 2018. Isle of Man historical wildlife records 1990 to 1994. Occurrence dataset: accessed via on 2018-10-01.

  12. National Trust, 2017. National Trust Species Records. Occurrence dataset: accessed via on 2018-10-01.

  13. NBN (National Biodiversity Network) Atlas. Available from:

  14. OBIS (Ocean Biodiversity Information System),  2023. Global map of species distribution using gridded data. Available from: Ocean Biogeographic Information System. Accessed: 2023-03-25

  15. Outer Hebrides Biological Recording, 2018. Invertebrates (except insects), Outer Hebrides. Occurrence dataset: accessed via on 2018-10-01.

  16. South East Wales Biodiversity Records Centre, 2018. SEWBReC Molluscs (South East Wales). Occurrence dataset: accessed via on 2018-10-02.


This review can be cited as:

Rowley, S.J. 2008. Trivia monacha Spotted cowrie. 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 25-03-2023]. Available from:

Last Updated: 08/05/2008