New Dinosaur Identified By Museum
A new dinosaur species identified by a Cleveland researcher 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, paleontologists said.
The dinosaur's large horns, thick as a human arm, are like those of triceratops — which came 10 million years later — but the 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 while a graduate student for the University of Calgary.
"Unquestionably, it's an important find," said Peter Dodson, a University of Pennsylvania paleontologist who studies horned dinosaurs. "It was sort of the grandfather or great-uncle of the really diverse horned dinosaurs that came after it."
Ryan named the new dinosaur Albertaceratops nesmoi, after the region and Cecil Nesmo, a rancher near Manyberries, Alberta, who has helped fossil hunters.
It's not only a new species but a new genus, the next step up from species in classifying living things. For example, people are genus Homo, species sapiens. The most general classification is kingdom (in this case, animals), followed by phylum, class, order, family, genus and species.
Features on the dinosaur's skull put it in a subfamily known as centrosaurs, which have large bony frills covering their necks and, usually, tiny spikes above their eyes that gradually disappear with age. About 20 feet long and weighing about half a ton, it lived 78 million years ago, making it the most primitive member of that subfamily.
"If you thought of the largest bull you could think of ... that's probably the size range this animal was like," Ryan said.
The large fan-shaped plate of bone sweeping out from its skull, called a frill, was edged with spikes, and two banana-shaped horns jutted out from the very top. Researchers believe they were meant to lure mates, not for attack.
The discovery helps sort out the evolutionary history of horned dinosaurs, Dodson said.
The oldest known horned dinosaur in North America is called Zuniceratops. It lived 12 million years before Ryan's find, and also had large horns.
That makes the newly found creature an intermediate between older forms with large horns and the small-horned relatives that followed, said State of Utah paleontologist Jim Kirkland, who with Douglas Wolfe identified Zuniceratops in New Mexico in 1998. He predicted then that something like Ryan's find would turn up.
"Lo and behold, evolutionary theory actually works," he said.