This small hydromedusa in the genus
Aglantha is bioluminescent, but the blue and purple colors in this
photo are formed by iridescence of thin tissues in its bell. The
thickness of the tissue and angle of light striking it can cause bright
colors to show up, similar to what happens with the
ctenophore Beroe, although produced by a different mechanism.
The orange color near the mouth is pigmentation, probably to mask
luminescence or attract prey.
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