A 70-million-year old dinosaur species possessed massive, scissor-like chompers that it probably used to gnaw through the tough, fibrous leaves of ancient palm trees. The discovery might help explain how multiple species of vegetarian dinos could co-exist in prehistoric Europe: this new dinosaur likely ate the parts of plants that no one else wanted.
The toothy dinosaur, described this week in the journal Scientific Reports, was discovered in the south of France among a jumble of bones from other dinosaurs and reptiles. Called Matheronodon provincialis, all that remains of this new species is an 8-inch long chunk of its right upper jaw, and a few loose teeth that may have come from other individuals. The researchers estimate based on the jaw size that this dinosaur could have grown to up to 16 feet long.
With nothing else to examine, paleontologists led by Pascal Godefroit at the Royal Belgian Institute of Natural Sciences took a close look at this dinosaur’s mouth. They found that its cleaver-shaped teeth were roughly two inches long front to back, and almost two and a half inches in height — a little shorter than if you stood your driver’s license on end. A CT scan revealed two sets of replacement teeth hiding in the jaw. Like in modern-day reptiles, these teeth would grow in to replace their cracked and worn predecessors.
Examining the teeth revealed that the surface you’d see if the dinosaur smiled was covered in thick enamel, and creased by more than 25 parallel ridges. That told the researchers this dinosaur was probably part of a family of dinosaurs called the rhabdodontids, vegetarians that roamed Europe between 84 to 72 million years ago.
But there were also key differences that set this new specimen apart; the teeth were more heavily ridged than those of other species, for example. That’s why the researchers decided that it needed its own name: Matheronodon provincialis, after Philippe Matheron, the paleontologist who first discovered a rhabdodontid in 1869.
Based on the muscle insertions on the jaw, the researchers suspect that Matheronodon had a powerful, slicing bite. The thick enamel along the front-facing surface of the teeth let the dinosaur sharpen its teeth by chewing. These serrated, shears-like jaws weren’t the jaws of a carnivore, or of a dinosaur that munched on easily-crushed fruit, for example. These teeth look like they evolved to cut through the tough, fibrous leaves of ancient palm trees.
Right now, that’s just educated speculation. To be certain about what Matheronodon actually ate, paleontologists will need more conclusive evidence: fossilized dinosaur poop. Until then, researchers will have to be content with studying this dinosaur’s charming grin.