Description: This feather star is larger than Antedon bifida and has a neater appearance and different coloration. The arms are either brown or red and white with the colour in large patches rather than the freckled appearance of Antedon bifida. There are more cirri, about 50-100 arising around a low hemispherical plate, and the lower side of the arm has an almost smooth outline. Arms typically 7-10cm in length.

Habitat: Found mostly in sheltered habitats attached to kelp, sessile animals or directly to wrecks or boulders.

Distribution: A northern species in the British Isles, at least in shallow water, frequent in the northern part of the Irish Sea and inshore in the west of Scotland, also around Shetland.

Similar Species: Similar to Antedon bifida but replacing this species in the north and in deeper water.

Key Identification Features:

• Ten neat feather-like arms, coloured in large patches.
• 50 short banded cirri of about 15 joints.
• Lower side of arm and pinnules with smooth outline.

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

iNaturalist: Antedon petasus at iNaturalist World Species Observations database.

WoRMS: Antedon petasus at World Register of Marine Species. Accepted name: Antedon petasus (Düben & Koren, 1846). AphiaID: 124210.

Classification: Biota; Animalia; Echinodermata; Crinozoa; Crinoidea; Articulata; Comatulida; Antedonoidea; Antedonidae; Antedoninae; Antedon