Fossil fish eye has 300 million-year-old rods and cones

Examining the eye of a beautifully preserved specimen of the ancient jawed fish Acanthodes bridgei from a 300 million-year-old rock formation in Kansas, scientists have found the first evidence of fossilized rods and cones. Located in the retina, these important cells absorb light and allow animals to see both color and contrast, but the delicate structures usually decay quickly after an animal’s death. Quick burial in a lagoon environment helped preserve this fossil. Early fish saw life in color, Gengo Tanaka of Kumamoto University in Japan and colleagues report December 23 in Nature Communications.