When James Clark was a teen-ager, he stole some window screen and sifted through the sand dunes around Los Angeles to find a shark's tooth.
He has been finding buried treasure ever since.
Mr. Clark's most recent discovery is a dinosaur "furcula," commonly known as a wishbone, found in the Gobi Desert in Mongolia. The paleontologist and professor of biology at George Washington University in the District discovered the fossil during a 1991 expedition, announced last month in the journal Nature.
The discovery is the first evidence of a wishbone in a Velociraptor, which belongs in a group of dinosaurs believed to be the closest relatives of birds. The V-shaped, slender wishbone provides further evidence that birds evolved from dinosaurs, Mr. Clark said.
"The furcula is recognizable to anyone who has ever broken the wishbone of a Turkey after Thanksgiving dinner, and it is connected to the same bones in the front of the chest," said Mr. Clark, who earned his doctorate from the University of Chicago.
Wishbones are typically present in flying creatures. The Velociraptor did not fly, so the bone's presence means the wishbone was adopted for another use, he said.
Mr. Clark also contributed to the Encyclopedia of Dinosaurs, released this month by paleontologists Phillip Currie and Kevin Padian. The book is geared toward paleontology aficionados who want the latest scientific information. Mr. Clark's entry, "Crocodylia," discusses how crocodiles descended from dinosaurs.
The discovery of the Velociraptor furcula flies in the face of new research that has challenged the traditional thinking that birds evolved from dinosaurs.
Researchers at the University of North Carolina at Chapel Hill have found that birds lack the embryonic thumb print of dinosaurs, suggesting it is almost impossible for the species to be closely related.
But Mr. Clark disputes that analysis: "First of all, there is insufficient developmental evidence," he said. "Fingers are highly modified. Things may have been moved around in the development of the bird hand, and we just don't have the evidence."
Other body parts - such as the legs, pelvis, skull and vertebrae - show overwhelmingly that birds did evolve from dinosaurs, he said. …