Missing Link" Dinosaur Discovered in Montana

14 October 2007 | 04:26 Code : 15604 Geoscience events
An unusual new species of dinosaur discovered in a Montana fossil provides....

An unusual new species of dinosaur discovered in a Montana fossil provides a long-sought link between a primitive group of dinos in Asia and those that roamed North America, experts say. The newfound species is a very early form of ceratopsian, whose descendants are best known for their fearsome horns and flashy neck frills. The ancient animal revealed by the fossil, however, had no horns and walked on two legs instead of four, scientists report. Moreover, the dino had extra teeth in its beaklike mouth that had never before been seen in an American specimen. Dubbed Cerasinops, the fossilized female amounts to a missing link between two dinosaur groups that lived half a world apart some 80 million years ago, said Brenda Chinnery-Allgeier, a University of Texas paleontologist who identified the new species. "Cerasinops is exciting because of the traits that she has—some are known only in Asian groups, and other are known only from North American groups," she said in an email to National Geographic News. While the newfound species had the teeth of an Asian ceratopsian, she explained, it had chewing mechanisms that were unique to American dinos. "The new dinosaur shows a direct link between Asian and North American horned dinosaurs that has been looked for for a long time," Chinnery-Allgeier said. "We knew that [the two groups] were related, but we didn't have any fossils that showed a mixture of characteristics like this and thus [demonstrated] the split between the Asian group and the North American group." Weighing some 40 pounds (18 kilograms) and standing 3 feet (1 meter) tall, Cerasinops was about the size of a large turkey. But it was impossible to tell exactly what kind of dinosaur it was when paleontologist Jack Horner first found its fossil skeleton near the town of Choteau in 1983 (see Montana map). "I discovered this skeleton 24 years ago after sitting on it having lunch," said Horner, curator of paleontology at MontanaStateUniversity's Museum of the Rockies, by email. It was preserved in reddish rock and was very difficult to see in the rock." After a team of experts prepared—or removed rock from—the fossil, the dino's distinct features began to take shape, Horner said. But it would be decades before scientists knew enough about so-called protoceratopsians to find the animal's place in the dinosaur family tree. "I knew when it was prepared that it was probably a new species, but there weren't any researchers at that time that focused on protoceratopsians," Horner said. "So the specimen waited for 24 years before someone—Brenda—came along that could do the specimen justice." Cerasinops's fossil skeleton, flecked with red from deposits of jasper trapped in the bones, will go on display at the Museum of the Rockies in Bozeman this winter, Horner added.

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