Of all dinosaurian visions ever committed to canvas, few are as famous as Charles R. Knight’s depiction of a duel between Tyrannosaurus and Triceratops. In the mural, hanging on the wall of Chicago’s Field Museum, the titans stand poised to lash out at each other in a flurry of horns and teeth. And this is often how we think of dinosaur combat – ambushes and stand-downs between predator and prey. Often overlooked are the fights dinosaurs had among their own species.

In the ever-growing ranks of known dinosaurs, members of a major group called the Ornithischia are often cast as relatively peaceful herbivores. These are the tusk-toothed heterodontosaurids, spike-thumbed iguanodonts, shovel-beaked hadrosaurs, spike-tailed