A modest little dinosaur that scampered across northwestern China 160 million years ago boasted a unique trait not seen in any other dinosaur or other prehistoric creature yet unearthed: it was born with teeth but became toothless by adulthood.
Scientists on Thursday said fossils of 19 individuals of a dinosaur called Limusaurus, ranging in age from under a year to 10 years, showed that juveniles had small, sharp teeth but adults developed a toothless beak.