Description: This is a bright orange, cushion shaped sponge, usually 6-7 mm thick but it can be up to 30 mm. It is found in patches 2-5 cm across, with an irregular outline. The patches are rounded in cross section with steep sides. It turns black or brown when placed in alcohol.

Habitat: This species can be found on lower infralittoral and upper circalittoral rock but is most frequently encountered on lower circalittoral bedrock on exposed open coasts.

Distribution: Known recently from various sites on the west, north-east and south-east coasts of Ireland, also St Abbs, Coll and Lewis.

Similar Species: Superficially there might be confusion with Amphilectus fucorum but there are distinct spicule differences. The blackening of M. fimbriata in alcohol is rapid and striking, and this combined with a lack of slime in what is otherwise a typical Myxillid skeleton makes this species distinctive from other Myxillid species such as Myxilla rosacea and Myxilla incrustans.

Key Identification Features:

• Bright orange cushion sponge, typically 6-7 mm thick.
• Found in patches 2-5 cm across.
• Goes black/brown in alcohol.

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

iNaturalist: Myxilla fimbriata at iNaturalist World Species Observations database.

WoRMS: Myxilla fimbriata at World Register of Marine Species. Accepted name: Myxilla (Myxilla) fimbriata (Bowerbank, 1866). AphiaID: 169461.

Classification: Biota; Animalia; Porifera; Demospongiae; Heteroscleromorpha; Poecilosclerida; Myxillidae; Myxilla