The trio of bones were some of the smallest pieces of dinosaur I had ever seen. Royal Ontario Museum paleontologist David Evans brought the rugose, chocolate colored pieces in a box smaller than my hand, set down next to a cast of a young dinosaur’s skull that looked absolutely enormous by comparison. Despite the difference in scale, though, the facsimile cranium and the authentic fossils shared a great deal in common and revealed the identity of the animal Evans had brought out to show me. What I was looking at was the smallest Pachycephalosaurus ever found.

The three bones—part of the cheek, the midline bone at the back of the skull, and a bone with small spikes jutting from it—were found