BEIJING: Scientists have discovered a dinosaur fossil buried hundreds of metres underground, not at a traditional excavation site but inside a drill core from a copper mineral resources survey in north China's Inner Mongolia Autonomous Region.
A research team of members from the nuclear industry and paleontology research institutions published the finding online Thursday in the journal Earth History and Biodiversity. According to the study, the dinosaur bones were found 473.2 metres down in a drill core in 2023. They were preserved in the upper part of the Bayan Gobi Formation, a geological layer of ancient sediment dating to the Early Cretaceous, about 120 million years ago.
Dinosaur fossils found in drill cores are extremely rare worldwide, said co-author Xing Lida, a dinosaur expert from China University of Geosciences (Beijing). One of the most famous cases occurred in 1997, when an exploration well at the Snorre oil field in the northern North Sea struck a crushed limb bone in a drill core about 2,256 metres below the seabed. Scientists later identified it as a plant-eating dinosaur. The discovery showed that the area was then a vast alluvial plain crossed by rivers, not the seabed.
Like the Norwegian one, the fossil found in north China is "a reminder that drill cores deep underground, seemingly relevant only to mining, can also hold keys to the ancient world," Xing said.
According to the study, the specimen includes part of a rib, four tail vertebrae and six bony arches from the tail. The bones had not yet fused, suggesting the dinosaur died as a juvenile.
The research team then compared the new specimen's tail bones in detail with those of more than 20 other bird-hipped dinosaurs.
The tail bones most closely resembled those of Psittacosaurus, a small plant-eating dinosaur known for its parrot-like beak.
The dinosaur species lived in the Early Cretaceous of East Asia, measured about 1 to 2 metres long and walked on its hind legs. It is one of the most common dinosaurs in the region, with fossils found in China, Mongolia and Siberia.
However, because the fossil material is limited, the researchers did not list it to a specific genus or species. They left it as an unidentified bird-hipped dinosaur.
The specimen also has a surprising feature: a row of tiny holes on its tail bones. Researchers have not reported such holes in other bird-hipped dinosaurs.
The researchers think they were probably normal openings for blood vessels and nerves. But because the dinosaur may have been young, it is still unclear whether the holes signalled species differences, individual variation, or a temporary stage of growth.
The Bayan Gobi Formation is an important Early Cretaceous dinosaur site in north China. Researchers have found many fossils of different dinosaur species there before. This new find offers fresh information about the range of dinosaur body shapes and features in the formation, Xing noted.
He added that the specimen was collected by the Inner Mongolia Museum of Natural History and will soon go on public display. - XInhua
