Species description: This fan worm has a crown of blue-purple tentacles (radioles) with 4-8 (occasionally 9) heavily pigmented bands, and a light yellow coloured body that has some black speckles present. There are 1-6 (most commonly 4-6) pairs of eyes on the dark bands on the radioles The tube is very silty and shorter than that of other native sabellids, and when out of the water the tube flattens, the end is closed over and is very square.

Habitat: On hard substrata in marinas and harbours.

Distribution: First recorded in Northern Ireland in 2024 on oyster cages in Bangor marina, now seems well established in this location. First recorded in Britain in two marinas in Plymouth in 2021, and so far only known from these locations. Any new records should be reported.

Similar Species: Could be confused with other fan worms but this is the only one with blue-purple tentacle crown and it also has distinctive tubes that flatten when out of the water.

Key Identification Features:

• Blue-purple crown of radioles (tentacles).
• 1-6 pairs of eyes on the heavily pigmented bands on radioles.
• Distinctive tube which flattens out of water, with the end closing.
• Body yellowish with some black speckles.

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

iNaturalist: Bispira polyomma at iNaturalist World Species Observations database.

WoRMS: Bispira polyomma at World Register of Marine Species. Accepted name: Bispira polyomma Giangrande & Faasse, 2012. AphiaID: 740848.

Classification: Biota; Animalia; Annelida; Polychaeta; Sedentaria; Canalipalpata; Sabellida; Sabellidae; Sabellinae; Bispira