科技英语新闻:Australian scientists discover 'sharp vision' ancient predator

CANBERRA, Dec. 9 (Xinhua) -- Scientists from Australia's University of New England on Friday said they had discovered the remarkably fossil isa metre-long arthropod with excellent vision called anomalocaris from Emu Bay Shale of South Australia.

The scientists reported their finding on the anomalocaris in thescience journal Nature this week.

It is reported that anomalocaris is a fearsome ancient predator that swam in the Cambrian oceans 500 million years ago. The researchers said the presence of anomalocaris would have driven the development of protective adaptations in prey animals. Such an escalatory 'arms race' would have seen, for instance, the evolution of such adaptations in prey as shells, camouflage and burrowing into sediments. "It has been unbelievably frustrating being able to see eyes like these at fossil sites like the Burgess Shale (in the Canadian Rocky Mountains), but not have any details. It is really refreshing to have our ideas about these animals confirmed at last, " comments Simon Conway Morris, a palaeontologist at the University of Cambridge, the United Kingdom.

The research team was led by paleontologist Dr John Paterson, of the University of New England. He said the most surprising discovery of anomalocaris is the huge number of tiny hardened lenses in each eyes.

"When you consider that a modern housefly, for example, has about 3000 lenses, it's pretty impressive that an animal half a billion years old already has remarkable vision like this," Paterson said in statement.

"The fact that each eye in anomalocaris would have had over 16, 000 lenses means it would have very, very good resolution."

Paterson said the acute vision of Anomalocaris gave it a distinct advantage over competing predators and prey, as many Cambrian animals either had poor vision or were completely blind. Its acute vision rivals or exceeds that of most living insects and was probably comparable to predatory dragonflies today.

He said their findings support the idea that compound eyes evolved very early on in arthropod evolution, before the evolution of jointed legs or hardened exoskeletons.

The research team hopes they can find the more fossil remains of Cambrian creatures in the Emu Bay Shale.