Ophiothryx fragilis is a brittle star reaching a diameter of up to 16 cm. The central disc has
a diameter of about 2 cm and the five thick arms are around 7 cm long. The arms are densely covered
by numerous spines. The colour is variable: pink, red, beige, brown, sometimes uniformedly coloured, sometimes
multicoloured. Common brittle stars use to draw up their arms to catch food particles brought by water
movements. These particles are convey into the mouth by means of numerous tube-feet scattered along the arms.
These may frequently be seen emerging from seaweeds, sponges, rocks or sandy wrecks where common brittle stars
find current-swept hiding places and where they may live in dense groups.
It is found from surface to depths down to 500 m, in the Atlantic Ocean, the English channel, the North Sea
and the Mediterranean Sea.
Phylum Echinodermata, class Ophiuroidea, order Ophiurida, family Ophiothricidae, Ophiothryx fragilis (Abildgaard, 1789).
Tube foot: Tube-shaped element ending by a sucker-disc used to attach to subtratum or to bring food particles into the mouth.
Photograph: © Wilfried Bay-Nouailhat. Published with author's kind permission.
Ophiothryx fragilis, Bay of Concarneau, South-Brittany, West of France. Depth 9 meters.
Text: Anne Bay-Nouailhat © 2005-2008.
Translation: Anne Bay-Nouailhat © 2007-2008.
