MK sport the Sinosauropteryx lingyuanensis (right) and the Huadanosaurus sinensis (left). Illustration: Zhao Chuang" src="https://www.globaltimes.cn/Portals/0/attachment/2025/2025-04-08/e0af6e0f-a7ab-4441-83f5-5018e6a1fb41.jpeg" />

Restoration images of Huadanosaurus sinensis (left) and Sinosauropteryx lingyuanensis (right). Illustration: Courtesy of  the Institute of Vertebrate Paleontology and Paleoanthropology at the Chinese Academy of Sciences

A new study on two theropod fossils found in Northeast China's Liaoning Province has revealed ecological differentiation within one dinosaur family for the first time in Early Cretaceous, suggesting a potential connection with major geological destruction of the North China Craton.

Both fossils, dated to 125 million years ago, are exceptionally well preserved, with intact soft tissues and stomach contents. One is named as Sinosauropteryx lingyuanensis, the other as Huadanosaurus sinensis. 

Though belonging to the same family of Sinosauropterygidae,their biological features and stomach contents show ecological differentiation, the Global Times learned from the Institute of Vertebrate Paleontology and Paleoanthropology at the Chinese Academy of Sciences.

The Huadanosaurus fossil contains multiple mammals in its stomach, one of which was swallowed whole. Based on its robust teeth, well-developed jaw muscle attachments, and strong cervical vertebrae, researchers believe it likely captured and killed small prey using its powerful bite, then swallowed them whole. 

This pattern is different from previously found species in Sinosauropteryx, which tended to predate reptiles and small prey, or use limbs to tear them apart. 

Species within a single family typically share one ecological niche, but the Sinosauropterygidsfrom the Jehol Biota present three different predation strategies among small theropods from the Early Cretaceous of Northeast China, suggesting that dynamic crustal movements may have influenced theropod diversification.

Fossils of the Huadanosaurus sinensis (left) and the Sinosauropteryx lingyuanensis (right). Photo: Courtesy of the Institute of Vertebrate Paleontology and Paleoanthropology, Chinese Academy of Sciences

The North China Craton destructed during the Early Cretaceous formed numerous small and isolated rift basins. These basins likely fragmented terrestrial habitats, limited interspecies mixing, and intensified competition. Such selective pressures resulting from species competition within these isolated rift basins may have been one of the key factors contributing to the remarkably high diversity of theropod dinosaurs in the Jehol Biota.

By directly connecting dinosaur evolution to regional geological activity, this discovery provides a new framework for understanding the co-evolution of organisms and their environments, the Global Times learned from the team.

The research team is led by Wang Xiaolin and Zhou Zhonghe from the Institute of Vertebrate Paleontology and Paleoanthropology, Chinese Academy of Sciences, in collaboration with domestic and international institutions, and the study has been published on National Science Review.