According to the evidence provided by Limusaurus inextricabilis fossils, some young dinosaurs would shed teeth as they grew up.
Scientists say hatchlings would eat meat with their teeth and only used their beaks to “peck at plants” as adults. This is a surprising discover, as it has not been seen in any other reptile.
Limusaurus inextricabilis lived in what is now China around 150 million years ago. The first fossils were found around a decade ago.
“Initially, we believed that we found two different ceratosaurian dinosaurs from the Wucaiwan area, one toothed and the other toothless, and we even started to describe them separately,” said research leader Shuo Wang of Beijing’s Capital Normal University.
However, paleontologists then realized that the dinosaurs looked almost identical, with the exception of their teeth. They then found that the dinosaurs lost their teeth as they aged, making them the first known reptiles to do this.
Dr. Stephen Brusatte of the University of Edinburgh, who wasn’t part of the research, said: “Up until now, who would have thought that there were dinosaurs that had teeth as babies, started to lose them as they grew up and then ended up as toothless adults with beaks?”
“Nothing like this is seen in any other fossil vertebrate and the platypus is the only modern land-living vertebrate that does anything similar,” Brusatte continued.
The dinosaurs would switch from one “feeding type” to another as they aged. Later in life, having teeth would prove disadvantageous and so they would shed them.
“Other theropod dinosaurs in the group to which Limusaurus belongs are carnivores and I can’t help wondering whether the driver for such a life cycle change was to allow Limusaurus to capitalize on a more abundant food source as they became larger,” he said.