Paleontologists say a fossil discovery of a small, speedy plant-eating dinosaur in Canada extends our knowledge of dinosaur ecosystems of millions of years ago.

While dinosaurs are often thought of as large, fierce but slow-moving animals, the new specimen, the smallest plant-eating dinosaur species known from Canada, was a speedy runner, a team of Canadian and U.S. researchers report in the Journal of Vertebrate Paleontology.

Fossil remains show Albertadromeus syntarsus was about 5 feet long and weighed about 30 pounds, comparable to a large turkey, they said.

The configuration of its lower leg bones would have made it a fast, agile two-legged runner, the researchers said, and it probably used its speed to avoid predation by the many species of meat-eating dinosaurs existing at the same time.

Little has been known about the extent of smaller dinosaur species because their bones are more delicate and are often destroyed before being fossilized, paleontologists say.

"We are now starting to uncover this hidden diversity, and although skeletons of these small ornithopods are both rare and fragmentary, our study shows that these dinosaurs were more abundant in their ecosystems than previously thought," lead study author Caleb Brown of the University of Toronto said.

Specimens Albertadromeus suggest there's much yet to learn about dinosaur diversity and the structure of their communities, the researchers said.

"You can imagine such small dinosaurs filling the niche of animals such as rabbits and being major, but relatively inconspicuous, members of their ecological community," Anthony Russell of the University of Calgary said.