fish sees ancient world in technicolour
6 Oct 2005 by qmcqmmjcbp.d qmcqmmjcbp.d
The Australian lungfish - one of the world’s oldest fishes - may have better colour vision than humans
The Australian lungfish - one of the world’s oldest fishes - may have better colour vision than humans.
Scientists have discovered that these unusual fish have genes for five different forms of visual pigment in their eyes. Humans only have three. 
Helena Bailes, the researcher who carried out the work at the University of Queensland in Australia, said: “Lungfish are very large, slow-moving fish, so vision was always assumed to be of little importance”. However, the new findings show that the photoreceptive cells are bigger in the lungfish than in any other animal with a backbone.
Helena explained: “Their eyes seem designed to optimise both sensitivity and colour vision with large cells containing different pigments.”
Humans have three types of colour sensing photoreceptive cells (cones), each containing a different pigment gene tuned to red, green and blue wavelengths. Lungfish possess two additional pigments - which are tuned to longer wavelengths - that were lost in mammals, Bailes says.
Regarded as “living fossils”, lungfish have remained unchanged for over 100 million years. Behavioural research will now try to find out how the fish use their colour vision in the wild. This, says Bailes, will also give clues as to how early land based creatures used their eyes. “The only way to find out how the first creatures on land saw the world is to look at their closest living relative: the Australian lungfish,” she said.
