https://www.youtube.com/watch?v=_AxOnEg6hXs
“The back of the frill isn’t broad and squared off the same way that it is in an adult. In fact, the frill narrows towards the back,” Currie said. “It is very different than I expected.”
Scientists aren’t sure what purposes the frills serve, although some have speculated that it served to help ward off predators.