Researchers discovered a 163-million-year-old dinosaur that might have chirped like a bird, pushing the origins of birdsong back millions of years.
In movies and demonstrations, if dinosaurs are depicted in motion, they typically roar as the ferocious beasts that they were. But maybe we cannot judge a book by its cover in this case.
In a study published last week in PeerJ, researchers from the Chinese Academy of Sciences in Beijing described a brand-new dinosaur species found in 163-million-year-old rocks: the two-foot Pulaosaurus.
The ancient fossil gave researchers a nearly complete view of its skeleton, which allowed them to identify the new dinosaur as an early member of the duck-billed hadrosaur and horned dinosaur, The New York Times reports.
They found that it had an unusual throat, though the vocal capacity of dinosaurs has largely remained a mystery to scientists. Thus, it is one of two dinosaurs on record with a preserved throat.
That area of the body typically doesn’t survive the millions of years it takes a scientist to dig it back up. Dr. Xu, lead author of the study, told The New York Times that “you don’t always have these isolated bones preserved with other skull elements,” even when the skeleton is preserved.
In this extraordinary case, scientists could examine the Pulaousaurs’ throat bones. They concluded that it could have made birdlike sounds. There was only one other dinosaur found previously that seemed to possess this ability, and neither one of them was remotely related to birds.
A mysterious aspect of the dinosaurs comes to light. What sound did they make? Were they tweeting and chirping, rather than roaring at one another? Maybe it was a mix of different sounds, but the latest discovery changes the entire image of the dinosaurs, even in theory.
Were T. rexes tweeting at one another?
In the study, scientists described a new fossil from the Upper Jurassic Tiaojishan Formation, County Qinglong, Province Hebei, China.
The well-preserved snapshot of the small herbivore included “ossified laryngeal elements,” which suggests that “bird-like vocalization evolved early in non-avian dinosaur evolution,” as per the study in PeerJ.
Scientists named it after a Chinese legend of the “Pulao,” a dragon that could shout loudly, so it will always be remembered as a dinosaur species that might have made sounds, though more like a bird.
Two terrestrial dinosaurs that could have sounded like birds
When scientists compared the new specimen to the only other dinosaur to be discovered with its vocal anatomy intact—the armored ankylosaur Pinacosaurus—it appeared that the Pulaousaur shared a similar vocal set-up.
Although they lacked a voice box like birds, their bony larynx was “large and mobile enough to possibly help produce birdlike noises,” according to the New York Times. However, the Pinacosaurus lived millions of years after the Pulaousaur, so this anatomical structure was less developed.
Neither of these dinosaurs bears any relation to modern-day birds whatsoever. They aren’t related to any of their ancestors at all. Puzzling, as the discovery would suggest that this vocal capacity might have evolved in separate lineages. And it could have emerged in the earliest dinosaurs, over 230 million years ago.
“We hope that in the future we can find more specialized structures relating to sound so we can do research on how dinosaurs produced their voices,” Dr. Xu concluded to The New York Times.
Read the study in PeerJ.