Newly discovered Jurassic fossil offers clues to early dinosaur sounds

Scientists in China have identified a new small dinosaur species, Pulaosaurus qinglong, preserved with its skeleton intact and its final meal still visible inside its body — a rare find that is offering fresh insight into how early plant-eating dinosaurs fed and possibly communicated.

The fossil was discovered in a slab of Jurassic sandstone from Qinglong County in Hebei Province and dates back around 163 million years. Measuring just about 28 inches in length, Pulaosaurus qinglong is one of the smallest known dinosaurs from this period.

The study, led by palaeontologist Yunfeng Yang of the Institute of Vertebrate Paleontology and Paleoanthropology (IVPP) in Beijing, was published in the journal PeerJ.

The skeleton lies curled in a natural position, with the skull, spine, limbs, and hips still connected. Geological evidence from the site suggests the dinosaur lived in a humid, forested environment shaped by nearby volcanic activity.

Researchers believe the specimen had not yet reached adulthood. Its large eye opening and unfused bones in the neck and tail indicate it was still growing, suggesting mature individuals may have been slightly larger.

Based on skeletal features, the team classified Pulaosaurus as an early neornithischian — a group of small, bird-hipped herbivorous dinosaurs that later gave rise to duck-billed and horned species.

One of the most striking discoveries was a pair of ossified arytenoid bones near the lower jaw. These bones form part of the larynx, or voice box, and are rarely preserved in dinosaur fossils. In living reptiles, these structures are usually made of cartilage rather than bone.

In Pulaosaurus, the arytenoids are unusually long — reaching about 80 percent of the length of the lower jaw — a proportion similar to that seen in some modern birds. Scientists say this supports growing evidence that certain dinosaurs had more advanced vocal control than previously thought.

Inside the chest and abdominal area, researchers also found small pebbles and impressions consistent with plant seeds. Together with leaf-shaped teeth, this suggests Pulaosaurus fed on vegetation and swallowed grit to help grind food in its digestive system.

The fossil also preserves part of the hyoid apparatus, which supports the tongue. Its short structure indicates limited tongue mobility, meaning the dinosaur likely relied more on its beak and teeth than on complex tongue movements when feeding.

The discovery is particularly important because Pulaosaurus qinglong fills a gap in the fossil record of the Yanliao Biota, a well-known Middle Jurassic ecosystem in northern China that had previously lacked clear evidence of neornithischian herbivores.

Researchers say the find not only expands knowledge of early plant-eating dinosaurs but also adds to a growing body of evidence that complex vocal structures evolved independently in multiple dinosaur lineages.

While scientists cannot yet determine what Pulaosaurus sounded like, its preserved throat bones suggest that some dinosaurs may have produced calls more bird-like than once imagined.

By Vugar Khalilov