Ophiopsila aranea Forbes, 1845

Description: A large brittle star with long banded arms which lives in crevices. The arms are banded with light and dark brown and there is a reticulate mottled pattern of brown on the disc. The arm spines are flattened and arranged in groups of 6-8. The tentacle scales are shorter than those of Ophiopsila annulosa but still exceptionally large. Disc 10mm. arms 9x disc diameter.

Habitat: Lives in crevices and extends the long arms out into the water. At the Mewstone these crevices are in bedded shales.

Distribution: Apparently rare in the British Isles, recorded from the Mewstone near Plymouth where it is locally abundant. Also known from the west coast of Ireland.

Similar Species: Ophiopsila annulosa is similar but larger and more robust with more arm spines at each joint and a different habitat. Ophiothrix fragilis may adopt a similar habit of extending its arms from crevices and is much commoner.

Key Identification Features:

• Long banded arms emerging from rock crevices.
• 6-8 flattened arm spines.
• Large tentacle scales just crossing beneath arms.

Distribution Map from BioMar data for Ireland - Google Earth map:  download this placemark (not got Google Earth installed?)

Distribution Map from NBN: JNCC MNCR Seasearch data - Grid map : Interactive map : National Biodiversity Network mapping facility, data for UK.