Paleontologists have identified a new species from the Ankylosaurus dinosaur genus Zhongyuansaurus, using specimens discovered in Henan Province, China.

Ankylosaurids (Antirosaurididae) were a group of herbivorous tetrapods known for their sturdy, scute-covered bodies, distinct armor, leaf-shaped teeth, and club-like tails.

The earliest and most renowned ankylosaurid dates back to approximately 122 million years ago, while the last species went extinct around 66 million years ago during the mass extinction event.

The newly recognized species belongs to a previously monospecific genus of Ankylosaurus called Zhongyuansaurus.

It is named Zhongyuansaurus Junchangi and lived in the region now known as China.

Fossils were collected from the upper section of the Haoling Formation in Zhongwa village, Henan Province, China.

“The fossils are preserved within an area of about 9 m.²,” noted Dr. Ji Min Chang from the Henan Museum of Natural History.

“They are fragmented and show no overlapping preservation, indicating they belong to a single individual.”

“The specimen includes one right mandible, 14 free caudal vertebrae, seven fused terminal caudal vertebrae forming a rod-like structure, four ribs, one left humerus, one elongated metatarsal, and 41 osteoblasts of varying sizes and shapes.”

The right lower jaw of Zhongyuansaurus Junchangi. Image credit: Zhang et al., doi: 10.19800/j.cnki.aps.2023037.

Zhongyuansaurus Junchangi exhibits a unique autapomorphy, featuring at least five caudal armor plates arranged in a distinct shiny pattern resembling a swallow shape.

“Furthermore, it has a relatively slender mandible compared to the more robust mandibles found in advanced Ankylosaurina,” the paleontologist added.

“The anterior tip of the coronoid process differentiates it from Chamosaurus, extending only into the last two alveoli.”

“The distal caudal vertebrae are decorated with small osteoblasts, and the humerus has a shaft proportion enclosed within 0.46, distinguishing it from Zhongyuansaurus luoyangensis.”

“The discovery of Zhongyuansaurus Junchangi provides new insights into the evolution of ankylosaurs in the lower Cretaceous layers of Ruyang and enhances the species diversity within the Ruyang Dinosaur Fauna,” the researchers concluded.

Their paper was published in the journal Acta Palaeontologica Sinica.

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Ji-Ming Zhang et al. 2025. New ankylosaur material from the lower Cretaceous period in the Luyan Basin, Henan Province. Acta Palaeontologica Sinica 64(1): 60-73; doi: 10.19800/j.cnki.aps.2023037