Lagoon sandworm (Armandia cirrhosa)

Lagoon sandworm under microscope
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Lagoon sandworm fact file

Lagoon sandworm description

GenusArmandia (1)

This rare, small worm is ribbon-like in appearance, and has three eyes on its head. The body comprises of 26 or 27 segments, each of which bear bristles known as chaetae (1). The name of this group of worms, polychaetes, means 'many bristles'.

Length: 3-7 mm (1)

Lagoon sandworm biology

Very little is known of the biology of this species, but it appears to have an annual cycle, with the entire life cycle occurring within one year (4).


Lagoon sandworm range

This worm was discovered in Eight Acre Pond in Lymington, South Hampshire, in 1984. A large population was still present at this site in 1985 and the species remained in 1990. However, despite repeated surveys for this worm it has not been found since in this pond (3). In 1994 it was discovered nearby in Dorset, at Small Mouth Spit (Portland Harbour), and East Fleet Sandbank, but in very low numbers in both places (3). Outside of Great Britain it has been found in the Mediterranean region (4), the Adriatic, around Madeira and the eastern Atlantic coasts (3).

You can view distribution information for this species at the National Biodiversity Network Atlas.

Lagoon sandworm habitat

Inhabits muddy, shingle or sandy sediments in water of a salinity that is only slightly less than that of seawater (4).


Lagoon sandworm status

Classified as 'Insufficiently Known' but 'Possibly Endangered' in the British Red Data Book. Fully protected under Schedule 5 of the Wildlife and Countryside Act 1981 (2) and a UK Biodiversity Action Plan priority species (3).


Lagoon sandworm threats

The loss of this species at Eight Acre Pond may have been the result of changes in salinity or unsuitable drainage (3). As this little-known worm has such a restricted range and occurs in small numbers, it is particularly vulnerable to extinction in Great Britain. Habitat modification or pollution could have devastating effects on this mysterious species (4).


Lagoon sandworm conservation

The lagoon sandworm is included in English Nature's Species Recovery Programme; it is also a priority species under the UK Biodiversity Action Plan (UK BAP), and as such has a Species Action Plan. This Action Plan aims to maintain and enhance current populations, and where possible, restore lost populations (3). The species was added to Schedule 5 of the Wildlife and Countryside Act in 1988, and is now afforded full protection (4).

The UK Biodiversity Action Plan for this species is available at UK BAP.
There may be further information about this species available via the National Biodiversity Network Atlas.
View information on this species at the UNEP World Conservation Monitoring Centre.

Find out more

For more on this species see the Marine Life Information Network (MarLIN) species account:



This information is awaiting authentication by a species expert, and will be updated as soon as possible. If you are able to help please contact:


  1. White, N. 2000. Lagoon sandworm, Armandia cirrhosa. Marine Life Information Network: Biology and Sensitivity Key Information Sub-programme [On-line]. Plymouth: Marine Biological Association of the United Kingdom. (July, 2002)
  2. JNCC. (July, 2002)
  3. UK BAP Species Action Plan. (July, 2002)
  4. Bratton, J.H. (1991) British Red Data Books: 3, Invertebrates other than insects. JNCC, Peterborough.

Image credit

Lagoon sandworm under microscope  
Lagoon sandworm under microscope

© Roger Key

Dr Roger Key
Tel: +44 (0) 1845 567 292


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