Fish that walked on land .... missing link

Fish that walked on land is missing link in evolution
By Mark Henderson, Science Correspondent


AN EVOLUTIONARY missing link that was among the first fish to leave the sea and walk on land has been unearthed in the Canadian Arctic.

The fossil discovery illuminates a chapter in the history of life on Earth that was essential to the ultimate emergence of human beings. Tiktaalik roseae, which lived about 375 million years ago, has features that blur the distinction between fish and terrestrial limbed creatures.

The fossils found on Ellesmere Island, 600 miles from the North Pole, are a fine example of evolution in action. They have allowed scientists to freeze-frame a process of adaptation to land that took tens of millions of years, and which made possible the development of all the mammals, birds, reptiles and amphibians that have existed since.

Without creatures such as Tiktaalik there would have been no dinosaurs, no primitive mammals and none of the hominids such as Australopithecus africanus and Homo erectus that started the human family tree.

"This animal represents the transition from water to land ?- the part of history that includes ourselves," said Neil Shubin, of the University of Chicago, who led the discovery team. "It's as much a part of our history as, say, Australopithecus africanus." <snip>

Richard Lane, of the US National Science Foundation, said: "These exciting discoveries are providing fossil ?'Rosetta Stones' for a deeper understanding of this evolutionary milestone.

Independent experts said the find was spectacular. Andrew Milner, of the Natural History Museum, said: "Previous fossils representing this evolutionary event have really been fish with a few land characteristics, or land vertebrates with a few residual fish characteristics. These fossils show an animal that sits bang in the middle."

Details are published in Nature and casts of the fossils will be displayed from today at the Science Museum, in London.