From Laurel Hamers at Science News:
Tiny light-scattering structures that give today’s butterflies and moths their brilliant hues date back to the days of the dinosaurs.
Fossilized mothlike insects from the Jurassic Period bear textured scales on their forewings that could display iridescent colors, researchers report April 11 in Science Advances. The fossils are the earliest known examples of insects displaying structural color — that is, color produced by light bending around microscopic structures, rather than light being absorbed and reflected as with a pigment or a dye. Structural color is common in bird feathers and butterfly wings today, but finding such features in the fossil record can be tricky.More.
Anyone want to bet against finding color displays meant to communicate information in the Cambrian era, once we have got the tools?
See also: Stasis: When life goes on but evolution does not happen