Submersible and laboratory observations on Asteroschema tenue, a long-armed euryaline brittle star epizoic on gorgonians

In situ and laboratory observations of the biology and behaviour of the deep-sea, euryaline brittle star Asteroschema tenue Lyman, from Jamaica, are described. The brittle star is found clinging to the gorgonian Ellisella barbadensis at depths of 168 to 230 m off Jamaica, and is here restricted to this gorgonian. The brittle star, which is usually cryptically coloured, is active principally nocturnally, when it extends arm loops and employs the tube feet for microphagous filter-feeding. Locomotory activity is limited to extension and retraction along the gorgonian, achieved by means of unusual arm-loop patterns. Association with a gorgonian appears to b essential for the survival of the brittle star.