Scientist says ostrich study confirms bird 'hands' unlike those of...( iod for major features of the skeletons...)

The beginnings of arm bones and "fingers" begin to appear around day 8, Feduccia said. Those that would grow into the animals' thumbs, however, appear around day 14 and later disappear by about day 17.

"Because most such studies in birds have relied on embryos in the second half of development, usually at or near hatching, these studies have therefore used embryos that exhibit the form of fully developed chicks and have generated misleading results," he said. "Questions about development of bird hands were first addressed in 1821 by the famous German physician and anatomist Johann Friedrich Meckel for whom the cartilage of the lower jaw was named. But no one has produced convincing evidence for a thumb before. For us, this is very exciting."

The UNC evolutionary biologist has been a strong critic of the belief that dinosaurs gave rise to birds as some paleontologists have claimed since the 1970s. He also has been a major figure in the debate for 30 years.

"There are insurmountable problems with that theory," he said. "Beyond what we have just reported, there is the time problem in that superficially bird-like dinosaurs occurred some 25 million to 80 million years after the earliest known bird, which is 150 million years old."

Most of the bird-like dinosaurs were "looking at the meteor some 65 million years ago," he said, a reference to the giant meteor believed to have struck the Earth then and killed off all dinosaurs within a short time.

If one views a chicken skeleton and a dinosaur skeleton through binoculars they appear similar, but close and detailed examination reveals many differences, Feduccia said. Theropod dinosaurs, for example, had curved, serrated teeth, but the earliest birds had straight, unserrated peg-like teeth. They also had a different method of tooth imp
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Contact: Deb Saine
919-962-8415
University of North Carolina at Chapel Hill
14-Aug-2002