Fig. 1

Bioluminescence of the brittle star Amphiura filiformis. (a) Bright light, and (b) bioluminescent pictures of A. filiformis. (c) Schematic illustration of the bioluminescence reaction occurring in A. filiformis in which coelenterazine is oxidized via the enzymatic activity of a luciferase homologous to the Renilla luciferase19,20 to form the oxyluciferin in an excited state. Going down to a stable state, the oxyluciferin (i.e., coelenteramide) releases photons and carbon dioxide8,9. Scale bars: 0.5 cm.