Reconstruction of Acrotholus audeti

Scientists have unveiled a new species of bone-headed dinosaur, which they say is the oldest in North America, and possibly the world.

The dog-sized plant-eater had a dome-shaped skull that may have been used to head-butt other dinosaurs.

University of Toronto researchers say the new species, revealed in the journal Nature Communications, fills in gaps in the dinosaur family tree.

They believe more small dinosaurs like Acrotholus audeti await discovery.

Bone-headed dinosaurs, or thick-headed lizards, are known scientifically as pachycephalosaurs.

They are a strange group of herbivorous dinosaurs which possessed a thick-boned dome on the top of their skulls.

The dome may have been used for decoration or to head-butt other dinosaurs in combat.

The new find, Acrotholus, dates back to 85 million years ago.

It was about the size of a large dog, weighed about 40kg (88lb), walked on two legs, and had a skull composed of solid bone over 10cm (4 inches) thick.

Read more

Read more