Australia's lungfish is the world's most primitive (Image: Helena Bailes)

The first creature to crawl out of the water probably had a technicolour view of the land, say Australian researchers.Professor Shaun Collin and colleagues at the University of Queensland report their findings today in the journal BMC Evolutionary Biology Seeing in colour is an advantage for animals as they can differentiate between prey, he says.The researchers have been studying the retina of the Australian lungfish (), a living fossil that dates back 400 million years.These fish were hanging around in shallow waters just before the first land vertebrates evolved.Lungfish have lungs and gills so can survive in and out of water. And many scientists believe they are the closest living relative to the first land vertebrates.But amphibian, reptile, bird and mammal land vertebrates see in colour, and until recently scientists didn't know much about the lungfish's small eyes.The researchers sequenced the gene responsible for opsin, the visual pigment in the photoreceptor cells of the lungfish retina.They found all five photoreceptor genes that occur in various combinations in higher vertebrates.These genes code for rods and cones, which enable the lungfish to see ultraviolet and visible light, both of which are useful in seeing prey.The photoreceptors also allow the fish to see in dim and bright light."It's really hedging its bets between bright light and dim light and it's able to see quite clearly in both environments," says Collin.This is proving an advantage today, he says, because the rivers lungfish live in now tend to be quite murky from run-off.The researchers now plan to see if lungfish can discriminate between objects based on colour.This will include testing to see if males and females recognise each other by the colour of their underbelly.Birds and reptiles have retained all five photoreceptors present in lungfish. But humans have lost two, including the cone that allows ultraviolet vision.