Ancient armored fish fossils from Australia present some of the first definite fossil evidence of a forerunner to the human eye. Researchers analyzed the fossilized remains of 400-million-year-old Devonian placoderms — jawed ancestors of modern fish whose bodies were protected by thick bony armor. Palaeobiologists discovered that unlike all living vertebrate animals — which includes everything from the jawless lamprey fish to humans — placoderms had a different arrangement of muscles and nerves supporting the eyeball — evidence of an “intermediate stage” between the evolution of jawless and jawed vertebrates.