An ankylosaur larynx provides insights for bird-like vocalization in non-avian dinosaurs

A voice box (larynx) is unique for tetrapods and plays functional roles in respiration, airway protection, and vocalization. However, in birds and other reptiles, the larynx fossil is extremely rare, and the evolution of this structure remains largely unknown. Here we report the fossil larynx found in non-avian dinosaurs from ankylosaur Pinacosaurus grangeri. The larynx of Pinacosaurus is composed of the cricoid and arytenoid like non-avian reptiles, but specialized with the firm and kinetic cricoid-arytenoid joint, prominent arytenoid process, long arytenoid, and enlarged cricoid, as a possible vocal modifier like birds rather than vocal source like non-avian reptiles. Although bird-unique vocal source (syrinx) have never been reported in non-avian dinosaurs, Pinacosaurus could have employed bird-like vocalization with the bird-like large, kinetic larynx. This oldest laryngeal fossil from the Cretaceous dinosaur provides the first step for understanding the vocal evolution in non-avian dinosaurs toward birds. The earliest larynx discovered in fossil dinosaurs indicates that non-avian dinosaurs may have had bird-like vocalization.

Automated summary

Researchers have discovered a fossilized larynx of a dinosaur called Pinacosaurus grangeri, suggesting that non-avian dinosaurs may have had bird-like vocalization. This is the first laryngeal fossil from the Cretaceous dinosaur, providing insights into the vocal evolution in non-avian dinosaurs towards birds.