Description: The largest sea squirt in the British Isles. The test is thick and cartilaginous, pale grey in colour and covered with low raised bumps and ridges. The overall shape is conical, with a broad base and a tall, tapering oral siphon. 120mm tall x 80mm broad.

Habitat: Usually found in places with little water movement, attached to hard substrates.

Distribution: Confined to warm, sheltered sites in the extreme south of the British Isles. Common in Portland Harbour, Dorset, and known from Bantry Bay, SW Ireland. Common in rias in NW Spain and in the Mediterranean.

Similar Species: Very distinctive; size, shape and colour separate this species from all other British ascidians.

Key Identification Features:

• Large size
• Conical shape
• Bumpy grey surface of test.

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

iNaturalist: Phallusia mammillata at iNaturalist World Species Observations database.

GBIF data for Phallusia mammillata

WoRMS: Phallusia mammillata at World Register of Marine Species. Accepted name: Phallusia mammillata (Cuvier, 1815). AphiaID: 103724.

Classification: Biota; Animalia; Chordata; Tunicata; Ascidiacea; Phlebobranchia; Ascidiidae; Phallusia