Omg I can't believe I missed it! VOCAL DINOSAURS GANG, WE KEEP WINNING!! Not only did Pulaosaurus preserve laryngeal structures, not only it suggests it had an avian-like vocalization, it's placement as a neornithischian from the Jurassic suggests these structures were widespread across Dinosauria, and the reason we don't find it in other dinosaurs is because they are either lost or missidentified (as it was initially the case with Pinacosaurus's larynx).