All the dinosaurs did not make the same sounds, but some were capable of making calls similar to those of birds, according to a study published in the journal Communications Biology. That was the case with Pinacosaurus grangeri, a stocky, spiky tetrapod that lived in the late Cretaceous period, roughly 80 to 75 million years ago.
Paleontologists from the Hokkaido University Museum and the American Museum of Natural History have come to that conclusion after analyzing a fossil of the dinosaur's larynx. Beyond the variety of sounds that it was capable of emitting, the researchers also highlight the power of its call. The reasons were the same as those of his colleagues: attracting mates, tracking offspring, and defending territory.
In their work, the researchers recall that the hyolaryngeal apparatus (tongue and larynx) is a key evolutionary trait in tetrapods and is associated with their feeding, breathing and vocalization. In particular, they continue, the larynx is an entrance to the tracheal canal and participates in vocalization. For example, it determines the sound communication of the animal.
Despite previous studies addressing their morphology and composition, these paleontologists felt that research had offered little evidence of what dinosaurs might have sounded like when they tried to make noises with their throat-based organs. This is because most voice boxes are made of cartilage that does not fossilize well.
To shed light on this, the authors studied the fossilized remains of a Pinacosaurus grangeri dinosaur, a stubby, spiky tetrapod that lived in the late Cretaceous period, approximately 80 to 75 million years ago, and was unearthed in 2005 by another team of scientists. researchers working in Mongolia.
During the initial study of the remains, researchers surmised that the fossilized bones in her throat were used for breathing, not noise. But a closer look at two of the bones revealed that they were parts of a larynx. Those muscles could have been used to manipulate the bones of the larynx to modify the air passing through the throat, allowing the dinosaur to make a variety of sounds.
After this finding, the authors investigated the type of sound that it could emit. To do this, they compared the bones of their larynxes with those of various types of modern birds and reptiles. They found that part of the larynx was proportionally larger than its modern counterparts, suggesting that the creature was likely capable of making very powerful sounds.
They also found another part of the elongated larynx, which would have allowed the muscles of the trachea to modify the sounds emitted by the larynx, they point out in their analysis.
“The combination of the large arytenoid process, firm cricoid-arytenoid articulation, and long arytenoids have likely enabled Pinacosaurus to open the glottis easily as in birds and can be used for avian-like airflow regulation, especially by modifying a sound”, conclude the scientists after their analysis of the fossil.
The researchers suggest that if the dinosaur was capable of making bird-like types of calls, it most likely used them for the same reasons: attracting mates, tracking young, and defending territory.
