Description: This species has finely-branched tentacles with white main axes and black side branches. The body is brown with longitudinal dark streaks and is covered with long, hairy tube-feet. There are no spicules except in the tube-feet and tentacles. Up to 15cm in length.

Habitat: Usually lives amongst boulders in sheltered habitats, buried in mud or sand between the boulders. May also occur in mud, amongst horse mussels and with Thyone fusus.

Distribution: Found on all western coasts of the British Isles.

Similar Species: Several Thyone species are very similar and some names could turn out to be synonyms.

Key Identification Features:

• Tentacles with white main axes and black side branches.
• Habitat in mud between boulders.
• Spicules absent except in tail and tentacles.

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

iNaturalist: Thyone roscovita at iNaturalist World Species Observations database.

WoRMS: Thyone roscovita at World Register of Marine Species. Accepted name: Thyone roscovita Hérouard, 1889. AphiaID: 124676.

Classification: Biota; Animalia; Echinodermata; Echinozoa; Holothuroidea; Actinopoda; Dendrochirotida; Phyllophoridae; Thyone