Dimetrodon had a mouth full of novelty. Most conspicuous were several different tooth types in the sail-backed protomammal’s jaws – incisor-like teeth for gripping, stabbing canines, recurved rear ...

As the meat it ate came in bigger and bigger packages, an ancient predator found a solution — it evolved serrated teeth similar to steak knives, a Canadian study has found. Dimetrodon was a ...