PRIMITIVE deep-sea fish may have viewed the world much as we do. The elephant shark, which evolved about 450 million years ago, is the oldest vertebrate to have “the colour vision system we know as humans”, says David Hunt at University College London.
Until now, ancestors of modern sharks from 374 million years ago were the oldest known creatures to have both rods to see in dim light and cones, for bright light.
Now Hunt’s team has found that the elephant shark, Callorhinchus milii, has rod pigments. It also has two copies of the long-wavelength cone pigment gene, a duplication which may have given them trichromatic…
