Description: This worm is a very striking colour either orange, brick-red or vermilion and is 10-30 mm long and up to 10 mm wide. There are two large eyes on the back of the head with a large antenna between them and two smaller eyes on the underside. There are 2 lateral antennae which are around half the size of the large central antenna. There are 30-36 chaetigers. The notopods cover part of the back of the animal on each side, leaving a small bare section along the centre. There are 7-9 pairs of dichotomously branching gills on each side of the animal, and the notochatae which are longer, form a row behind them.

Habitat: Under boulders or among shells and algae from low water to shallow subtidal.

Distribution: There are scattered records around Britain and Ireland, although it seems to be absent from the east coast of Britain.

Similar Species: Could potentially be confused with Spinther oniscoides as they are similar in appearance and colour, but it feeds on sponges and is usually found there.

Key Identification Features:

• Strikingly coloured worm – orange, brick-red or vermilion.
• 10-30 mm long, 10 mm wide.
• Two large eyes dorsally, with large median antenna between them.
• Notopods cover part of back, leaving small bare section down midline.
• 7-9 pairs of dichotomously branching gills on each side, with a row of notochaetae behind.

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

iNaturalist: Euphrosine foliosa at iNaturalist World Species Observations database.

GBIF data for Euphrosine foliosa

WoRMS: Euphrosine foliosa at World Register of Marine Species. Accepted name: Euphrosine foliosa Audouin & H Milne Edwards, 1833. AphiaID: 130083.

Classification: Biota; Animalia; Annelida; Polychaeta; Errantia; Amphinomida; Euphrosinidae; Euphrosine