Description: This sponge may grow as a thin sheet or cushion, developing into ascending finger-like growths. The surface is irregular, with raised areas that are denser in appearance supported by the underlying skeleton, with a transparent surface membrane between these ridges. The colour is off-white, grey, through bright yellow to bright orange, blackening on contact with air and on preservation.

Habitat: On circalittoral bedrock and boulders under a wide range of wave exposures and current regimes. Also common on Terebratulina retusa a brachiopod that occurs sublittorally in sheltered sea lochs and in deep water on open coasts.

Distribution: Common and widespread in the English Channel, Ireland and W. Scotland.

Similar Species: Large specimens may superficially resemble Myxilla incrustans or Myxilla rosacea, however the blackening on death is very noticeable.

Key Identification Features:

• Turns black on exposure to air and on preservation
• Irregular surface
• Colony forms ascending finger-like growths

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

iNaturalist: Iophonopsis nigricans at iNaturalist World Species Observations database.

WoRMS: Iophonopsis nigricans at World Register of Marine Species. Accepted name: Iophon nigricans (Bowerbank, 1858). AphiaID: 132971.

Classification: Biota; Animalia; Porifera; Demospongiae; Heteroscleromorpha; Poecilosclerida; Acarnidae; Iophonopsis