Spookfish Uses Mirrored Eyes to See

Scientists at Tuebingen University have discovered that the deep-sea spookfish is the first vertebrate to develop natural mirrors to focus light into its eyes.

Known for about 120 years, this first live specimen of the brownsnout spookfish (Dolichopteryx longipes) was caught last year off the coast of Tonga. Spookfish generally live at ocean depths of 1000 meters or more and in near total darkness. Their two compound eyes consist of two parts each, one of which is a mirrored surface used to focus faint traces of light into an image on the other part.

These mirrors are made up of guanine crystals, a naturally occurring substance in fish scales that produces a pearly, iridescent effect and has a high reflectivity. The mirrored portions are curved in such a way as to focus the reflected light on the fish's retina.

These results appear in a recent issue of Current Biology.

Photo: BBC News