Fossils of oldest horned dinosaurs size of a bunny found in North America

Scientists announced the discovery of the fossil of the oldest known horned species of dinosaurs in North America earlier today. This creature, which was nearly as long as a crow and as heavy as a bunny, was a plant eating animal and lived in southern Montana nearly 108 million years ago. Called Aquilops americanus, it was closely related to similar dinosaurs found in Asia.

Aquilops were estimated to be about 2 feet long and 2.5 pounds, with a skull 3.3 inches long. They had sharp beaks which they used to snip off the plants they wanted to eat. They probably walked on two limbs, unlike later ceratopsians.

They lived about 40 million years before Triceratops and nearly 20 million years before Zuniceratops, the next oldest ceratopsian identified from North America. In all, the little dinosaur is quite different from celebrity ceratopsians such as Triceratops and Styracosaurus. Those dinosaurs were separated from this one not only by about 50 million years, says Cleveland Museum of Natural History paleontologist Michael Ryan, but also in size and shape.

“Aquilops is known from a skull and lower jaws, which allow us to nail down its position in the dinosaur family tree pretty precisely,” said paleontologist Andrew Farke of the Raymond M. Alf Museum of Paleontology in Claremont, California, who led the study published in the scientific journal PLOS ONE.

“Most importantly, Aquilops is far more closely related to horned dinosaurs from Asia than it is to horned dinosaurs from North America such as Triceratops. This shows that horned dinosaurs probably migrated into North America from Asia at least two different times, maybe even more,” Farke added.

Farke says, finding more of Aquilops will take a lot of luck. However even a single skull belonging to the Aquilops species is enough for the paleontologists to begin investigating into the manner in which they lived.

The next known horned dinosaur on the continent did not appear on the scene for nearly 20 million years after Aquilops and 40 million years after Triceratops lived, say the researchers. The findings were published in the Dec 10 issue of the journal PLOS ONE.