Researchers' team involving Fukushima Museum curator finds dinosaur's larynx fossil

A team of Japanese and U.S. researchers led by Fukushima Museum curator Junki Yoshida announced on Feb. 15 the world's first discovery of a non-avian dinosaur’s fossilized voice box, or larynx. A research report on the finding has been carried by the British scientific journal "Communications Biology." No fossils of organs related to respiration or the voice had been unearthed previously. Given the bones' configuration, the researchers believe the dinosaurs may have communicated in chirps like birds. "This is an important first step to deepen the understanding of the vocal evolution of dinosaurs," said Yoshida, 31. Other team members include Prof. Yoshiteru Kobayashi, 51, of the Hokkaido University Museum, and Dr. Mark Norell, 65, of the American Museum of Natural History. The bone set is part of the fossilized skeleton of a Pinacosaurus excavated by the U.S. museum in the Gobi Desert in Mongolia in 2005. The team began studying the fossils of the plant-eating dinosaur in 2018 when Yoshida was a guest researcher at the museum. The fossils were in good condition, with most bones connected. To seek clues to the evolution of bone structures associated with vocalization, the researchers compared unidentified bone pieces left in the dinosaur's skull with more than 100 laryngeal bone samples of contemporary avian and reptile species kept at museums in Japan and the United States. As a result, they concluded that they were the Pinacosaurus' larynx, which is composed of the cricoid and arytenoid -- cartilages connected by muscles and previously thought not to be fossilized. Their analyses of the larynx's kinetic cricoid-arytenoid joint structure and related functions found many similarities between the dinosaur larynx and that of birds. They believe that both were shaped to fit vocal communication and it is possible dinosaurs employed bird-like vocalization. At the Fukushima Museum in Aizuwakamatsu city, Fukushima Prefecture, an exhibition of duplicates of the fossil samples is under way through March 10. Pinacosaurus: A plant-eating dinosaur that lived during the Mesozoic era in the Cretaceous period (roughly 84 million to 72 million years ago); walking on four legs, it protects itself with armor-like skin and bones covering the back. It is believed that the dinosaur was about 5 meters in length and up to 1 ton in weight. Its habitat area was mainly Asia centering on China and Mongolia. Photo: Fukushima Museum curator Junki Yoshida (Translated by Kyodo News)