Horned dinosaur species called evolutionary link

Horned dinosaur species called evolutionary link


Associated Press
CLEVELAND — A newly discovered dinosaur species was a plant-eater with yard-long horns over its eyebrows, suggesting an evolutionary middle step between older dinosaurs with even larger horns and the small-horned creatures that followed, experts said.

The dinosaur's horns, thick as a human arm, are like those of triceratops — which came 10 million years later. However, this animal belonged to a subfamily that usually had bony nubbins a few inches long above their eyes.

Michael Ryan, curator of vertebrate paleontology for the Cleveland Museum of Natural History, published the discovery in this month's Journal of Paleontology. He dug up the fossil six years ago in southern Alberta, Canada, while a graduate student for the University of Calgary.

"Unquestionably, it's an important find," said Peter Dodson, a University of Pennsylvania paleontologist.

Ryan named the new dinosaur Albertaceratops nesmoi. The creature was about 20 feet long and lived 78 million years ago.

The oldest known horned dinosaur in North America is called Zuniceratops. It lived 12 million years before Ryan's discovery, and also had large horns. That makes the newly found creature an intermediate between older forms with large horns and later small-horned relatives, said State of Utah paleontologist Jim Kirkland.