New Giant Therizinosaur Dinosaur Discovered in China’s Early Cretaceous Jehol Biota

Paleontologists have described Kailasaurus changliensis, a new genus and species of therizinosaur dinosaur based on a nearly complete skeleton discovered in northeastern China. It is the largest therizinosaur known from the famous Early Cretaceous Jehol biota.

Kailasaurus changliensis lived in what is now China during the Early Cretaceous, approximately 125 million years ago.

It belonged to Therizinosauria, a group of unusual herbivorous or omnivorous theropod dinosaurs best known for their enormous hand claws. Although therizinosaurs were theropods, many later members evolved features more commonly associated with plant-eating dinosaurs, including small heads, elongated necks, leaf-shaped teeth, broad pelvises, shortened lower legs, and four-fingered hands.

“Therizinosauria is an anatomically strange and rare group of theropod dinosaurs,” said paleontologist Dr. Xin Shu of the Institute of Vertebrate Paleontology and Paleoanthropology of the Chinese Academy of Sciences and Yunnan University, along with colleagues.

“Later-branching taxa evolved unusual traits such as relatively small heads, elongated necks, leaf-shaped teeth, rostrally descended edentulous jaws, enlarged manual claws, broad, propubically tilted pelvises, shortened tibiae, and tetraphalanges.”

According to the researchers, the combination of these unusual features with the basic theropod body plan has contributed to the group’s complex taxonomic history.

A nearly complete therizinosaur skeleton from the Yixian Formation

The researchers recovered an almost complete skeleton of Kailasaurus changliensis, including a nearly complete skull, from the Yixian Formation in western Liaoning Province, China.

The Yixian Formation is part of the Jehol biota, a fossil-rich Early Cretaceous ecosystem that preserved numerous feathered dinosaurs and other ancient organisms.

The specimen measured more than 3.6 meters (11 feet) in length, making it at least 1.6 times longer than Beipiaosaurus, the second-largest therizinosaur known from the Jehol biota.

The paleontologists estimate that the dinosaur weighed approximately 117–274 kilograms (260–600 pounds). Because the individual was probably a subadult, fully grown Kailasaurus specimens may have been even larger.

Distinctive teeth, neck vertebrae, and hand claw

Kailasaurus changliensis had very small, densely packed teeth. More than 45 teeth were present in the lower jaw, the highest count recorded in any known therizinosaur.

The dinosaur’s neck vertebrae were longer than those in its back. One of the hand claws also had a distinctive upward-projecting “lip,” a feature that helps distinguish the new species from other therizinosaurs.

“The discovery of Kailasaurus changliensis provides an important new data point for understanding the evolution of early therizinosaurs,” the scientists said.

As the largest therizinosaur identified from the Jehol biota, Kailasaurus changliensis may help bridge the morphological gap between several previously known species.

Different body shapes may reflect different ecological strategies

The researchers compared Kailasaurus changliensis with three other therizinosaurs from the Jehol biota: Beipiaosaurus, Jianchangosaurus, and Linyuanosaurus.

Kailasaurus and Beipiaosaurus appear to have had more robust bodies, jaws adapted for stronger bites, and less agile physiques. By contrast, Jianchangosaurus and Linyuanosaurus had lighter builds that may have been better suited for running.

These differences suggest that the therizinosaurs occupied distinct ecological niches. However, the authors emphasize that this interpretation is preliminary and that more complete fossils will be needed to test the hypothesis.

“Integration of morphology, biomechanics, and body-size data suggests the existence of at least two distinct ecological strategies among Jehol therizinosaurs: one favoring oral processing and robust body construction, and the other favoring agility,” the authors said.

“While these ecological interpretations are still preliminary, they highlight the importance of continued fieldwork, new fossil discoveries, and biomechanical analyses to further uncover the evolutionary pathways and paleoecological diversity of this enigmatic group.”

The discovery of Kailasaurus changliensis is reported in a paper published in the Journal of Systematic Paleontology.

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Liao Chunchi et al. 2026. Ecomorphological patterns of new therizinosaurs and early therizinosaurs from the Early Cretaceous Jehol biota. Journal of Systematic Paleontology 24(2). doi: 10.1080/14772019.2026.2710287