Description: This worm lives in chalky tubes (1-3 mm) with distinctive flared collars at intervals along the tube. Occasionally these collars may be absent. The tubes are normally white, but freshly built tubes may have a fawn to horn brown colour. The worm itself has a feathery crown of tentacles which may be visible if the animal is submerged. There is an operculum that is covered with dark inward facing spines. The tubes can form reefs or dense mats.

Habitat: Sheltered sites such as ports, harbours and bays with reduced (or fluctuating) salinity.

Distribution: There is one record from Northern Ireland in Dundrum Bay (however there is no specimen or photograph to support this). Most records in Britain and Ireland are from the south of Britain.

Similar Species: Could be confused with other species of worm that builds chalky tubes, however the distinctive flared collars spaced along the tube will help distinguish this species. The operculum is also distinctive.

Key Identification Features:

• Usually has distinctive flared collars on the chalky tube.
• Distinctive operculum with dark, inward facing spines.

Distribution Map from NBN: Ficopomatus enigmaticus at National Biodiversity Network mapping facility, data for UK.

iNaturalist: Ficopomatus enigmaticus at iNaturalist World Species Observations database.

GBIF data for Ficopomatus enigmaticus

WoRMS: Ficopomatus enigmaticus at World Register of Marine Species. Accepted name: Ficopomatus enigmaticus (Fauvel, 1923). AphiaID: 130988.

Classification: Biota; Animalia; Annelida; Polychaeta; Sedentaria; Canalipalpata; Sabellida; Serpulidae; Serpulinae; Ficopomatini; Ficopomatus