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lunes, 30 de marzo de 2009

Scientist Discovers New Horned Dinosaur Genus


Dr. Michael J. Ryan with the holotype skull of the new horned dinosaur, Albertaceratops nesmoi, from southern Alberta, Canada. (Credit: Photo courtesy of Chad Kerychuk, Digital Dream Machine)

A scientist at The Cleveland Museum of Natural History has announced the discovery of a new horned dinosaur, named Albertaceratops nesmoi, approximately 20 feet long and weighing nearly one half ton, or the weight of a pickup truck. The newly identified plant-eating dinosaur lived nearly 78 million years ago during the Late Cretaceous Period in what is now southernmost Alberta, Canada. Its identification marks the discovery of a new genus and species and sheds exciting new light on the evolutionary history of the Ceratopsidae dinosaur family. Only one other horned dinosaur has been discovered in Canada since the 1950s.
Michael J. Ryan, Ph.D., Curator of Vertebrate Paleontology at the Museum reports his findings on the new genus and species in the latest volume of the Journal of Paleontology.

Albertaceratops nesmoi belongs to the Centrosaurinae, one of two subfamilies of the horned dinosaur family Ceratopsidae. Typically members of this subfamily have very short horns over their eyes, a long horn over their nose and either spikes or hooks coming off of the frill that projects from the back of their skulls.

What makes this dinosaur unique is that it is the first centrosaur with long brow horns typically found in the other subfamily, Chasmosaurine, which includes Triceratops and Torosaurus. In addition, Albertaceratops nesmoi lived more than 10 million years earlier than Triceratops.

“My research team was stunned when we uncovered the skull and saw these long brow horns attached to a centrosaurine frill,” said Ryan, a Canadian who was working on his Ph.D. through the University of Calgary when the specimen was found.

“We knew that we had something special that we had never seen before—it meant that while Triceratops had giant horns, some centrosaurs did, too,” he added.

In addition to having long brow horns, Albertaceratops nesmoi has a long, low banana-shaped bump in place of a nasal horn. There also are two large, thick hooks that curl forward from the corners of the creature’s frill. The long horns could have been used for either sexual display or self-defense against the giant predatory tyrannosaur, Daspletosaurus that roamed the region.

“Analysis shows that Albertaceratops nesmoi was the most primitive member of the Centrosaurinae, and that it is placed just above the split that separated them from the group that includes Triceratops,” Ryan added.

“It is very surprising that a Centrosaur would have long brow horns,” said Don Brinkman, Ph.D., Head of Research and Curator of Vertebrate Paleontology at the Royal Tyrrell Museum in Drumheller, Alberta, where the specimen is currently housed.

Albertaceratops nesmoi is named to honor both the province where the new dinosaur was found and Cecil Nesmo, a local rancher living near Manyberries, Alberta, who has long supported the study of palaeontology and other research in the area.

Ryan had spent four hot summers looking for long-horned centrosaurs in southern Alberta after being shown similar fossils owned by Canada Fossils. Ltd., Calgary, which had been collected from just across the border in Montana.

“The most southern part of Alberta has a tremendous potential for discovering new dinosaurs, but it has been almost ignored in the past because of its remoteness,” said David Evans, incumbent Associate Curator of Dinosaurs at the Royal Ontario Museum in Toronto.

For this reason, Ryan and Evans established the Southern Alberta Dinosaur Research Group (SADRG) (http://www.dinoresearch.ca) in 2005 along with colleagues from the Royal Tyrrell Museum, The University of Alberta and the University of Calgary.

According to Ryan, the support of local ranchers and families living along Alberta’s southern border is key to conducting scientific research in the area. “In addition to facilitating the exchange of scientific information and educating students, the SADRG helps researchers coordinate their work with each other, government agencies and the local residents so that everyone’s concerns are met,” said Ryan.

Ryan and the SADRG have their next three field seasons mapped out, and are close to announcing at least one more new, strange-horned dinosaur.

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