Description: A medium-sized brittle star with very long arms which lives buried in sand. The dorsal and ventral surfaces of the disc are covered in scales. Those of the ventral surface and the edge of the disc bear small tubercles. There are 8-10 short conical arm spines and 2 tentacle scales. Disc to 13mm, arms 15x disc diameter.

Habitat: This brittle star burrows in clean sand from low water mark to 40m, commoner in shallow water. Often associated with Echinocardium cordatum.

Distribution: South and west coasts of the British Isles, probably also on North Sea coasts.

Similar Species: Larger and coarser than other Amphiura species, none of which have tubercles on their disc scales. Amphiura chiajei is most similar but never has more than six arm spines and has smooth ventral and marginal disc scales.

Key Identification Features:

• Medium sized disc and very long arms.
• Lives buried in sand.
• Upper and underside of disc covered in scales.
• 2 Tentacle scales in proximal parts of arms.
• 8-10 short, neat arm spines.

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

iNaturalist: Acrocnida brachiata at iNaturalist World Species Observations database.

WoRMS: Acrocnida brachiata at World Register of Marine Species. Accepted name: Acrocnida brachiata (Montagu, 1804). AphiaID: 236130.

Classification: Biota; Animalia; Echinodermata; Asterozoa; Ophiuroidea; Myophiuroida; Metophiurida; Ophintegrida; Amphilepidida; Gnathophiurina; Amphiuroidea; Amphiuridae; Acrocnida