As seen on a wire service Friday, January 14, 1994; SOURCE: Associated Press. DATELINE: WA

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As seen on a wire service Friday, January 14, 1994; SOURCE: Associated Press. DATELINE: WASHINGTON `COMPLETE' WHALE FOSSIL FOUND WITH HIND LEGS Researchers have found the fossil remains of an ancient relative of the whale that was able to walk on land. "This critter is a missing link between land animals and modern whales," said J.G.M. Thewissen, a paleobiologist at Northeastern Ohio Universities College of Medicine in Rootstown, Ohio. "It is a very complete specimen and has enough of the anatomy to teach us something about how the animal moved on land." A report on the discovery is to be published Friday in the journal Science. Thewissen said the fossil was found in deposits left by an ancient sea that once existed in Pakistan. Fossils found nearby, he said, suggest that the whale died about 50 million years ago. "It was about the size of a big male sea lion and probably weighed 600 to 700 pounds," said Thewissen. Many fossils of the land-dwelling ancestors of the modern whale have been found, but Thewissen said this is the first with enough fossils of the legs, vertebrae and tail to show how the animal was able to move on land and in the water. The animal, which Thewissen calls Ambulocetus natans, had large rear feet with fully developed legs. In front, the feet are short, stubby and joined almost to the shoulder. As a result, the walking whale actually moved by bumping along on its chest and abdomen, just lifting itself enough to lurch forward. "That makes it look kind of clumsy," said Thewissen. He said sea lions and seals appear clumsy on land, but they are able to move short distances at a speed faster than most people can run. In the water, Thewissen said the ancient whale probably swam with thrusts from its hind feet and legs. He said the bones suggest there were large muscles in the back that would give the legs great power for water propulsion. Its tail, however, was probably long and lacked the distinct fluke of modern whales, which swim by thrusting the tail fluke up and down. Ambulocetus natans had the teeth of a meat eater, but because it was so awkward on land it probably was unable to catch prey out of the water. For this reason, Thewissen speculates that the whale ancestor lived on marine life, as do modern whales. Modern whales are thought to have developed from animals that lived on land and slowly, over thousands of generations, evolved to the seabound mammal known today. "The oldest skeleton that is a marine whale is about 40 million years old," said Thewissen. That skeleton is 40 to 50 feet long and had tiny hind feet. "Given the size of that animal, it is clear that it couldn't move on the land." Ambulocetus natans lived about 10 million years before that, but Thewissen said there are a number of missing links in the evolutionary chain that became the modern whale. "The first true whale was probably about the size of a big wolf," said the researcher. That contrasts with the modern blue whale which can be up to 100 feet long and weigh 220 tons.


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