Description: This sponge consists of a thick spreading cushion, with raised ridges. The colour is usually pale to sulphur yellow. The surface is distinctive, it consists of numerous deep labyrinthine channels, across which run cobweb-like strands of tissue.

Habitat: Frequent on vertical and gently sloping sublittoral bedrock in areas exposed to wave action or strong tidal streams.

Distribution: Recently known from several sites around the British Isles.

Similar Species: May be confused with Iophonopsis nigricans but this species becomes black on contact with air and on preservation. It is also similar to Myxilla rosacea which is usually pink to orange in colour but may also be yellow. Initially identification will need to be checked by careful examination of the spicules.

Key Identification Features:

• Open labyrinthine texture to surface
• Massive yellow sponge

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

iNaturalist: Myxilla incrustans at iNaturalist World Species Observations database.

WoRMS: Myxilla incrustans at World Register of Marine Species. Accepted name: Myxilla (Myxilla) incrustans (Johnston, 1842). AphiaID: 169466.

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