115-Million-Year-Old Dinosaur Fossil Found in Deep Drill Core Expands Fossil Range in China

Chinese geologists conducting a copper mineral survey in Inner Mongolia have unexpectedly recovered a 115-million-year-old dinosaur fossil from a drill core 473 metres (1,500 feet) deep, near Guaizihu in the Yin'gen-Ejinaqi Basin. The fossil, catalogued as 208GPV01, is the first dinosaur record from the remote western section of the Bayan Gobi Formation, an Early Cretaceous rock unit in western Inner Mongolia, extending the known geographic range of dinosaur fossils in this formation. The findings were published on September 5, 2026, in the journal Earth History and Biodiversity by Dr Lida Xing of the China University of Geosciences and the Dinosaur Odyssey Science Museum, and colleagues.

The specimen consists mainly of proximal tail vertebrae and associated elements, including a sacral rib, four caudal vertebral centra, six caudal neural arches, several transverse processes and ossified tendons. The researchers classified it as belonging to Ornithischia, a group of plant-eating, bird-hipped dinosaurs. Using a method called geometric morphometrics, which compares the shapes and proportions of bones, they compared the fossil's proportions with those of numerous other ornithischian species.

The analysis showed the specimen's vertebral proportions most closely resemble those of Psittacosaurus, an early horned dinosaur that was common across Cretaceous East Asia. Because the material recovered is limited, the researchers stopped short of assigning it to a specific genus or species, classifying it for now only as an indeterminate ornithischian.

The Bayan Gobi Formation had previously yielded dinosaurs including the hadrosauroid Penelopognathus weishampeli, the ceratopsian Psittacosaurus sibiricus and the alvarezsauroid Bannykus wulatensis, but nearly all these finds came from the eastern part of the Yin'gen-Ejinaqi Basin. The researchers noted that the fauna of the formation shares similarities with the nearly contemporaneous Western Liaoning fossil beds, suggesting both may belong to the radiation range of the Jehol Biota, although some differences exist.