Paleontologists have described a new species of the ankylosaurid dinosaur genus Zhongyuansaurus using a specimen found in China’s Henan province.
Life reconstruction of Zhongyuansaurus junchangi. Image credit: Connor Ashbridge / CC BY 4.0.
Ankylosaurids (family Ankylosauridae) were herbivorous quadruped dinosaurs known for their robust, scute-covered bodies, distinctive body armor, leaf-shaped teeth, and club-like tails.
The earliest-known ankylosaurids date to around 122 million years ago, and the youngest species went extinct 66 million years ago during the end-Cretaceous extinction.
The newly-identified species belongs to a previously monospecific ankylosaurid genus called Zhongyuansaurus.
Named Zhongyuansaurus junchangi, it lived in what is now China during the Albian age of the latest Early Cretaceous.
The dinosaur’s fossilized remains were collected from the upper part of the Haoling Formation at Zhongwa village in Henan province, China.
“The fossils are preserved within an area of about 9 m2,” said Dr. Ji-ming Zhang from the Henan Natural History Museum and colleagues.
“They are disarticulated and show no overlapping preservation, suggesting 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, 10 haemal arches, one left humerus, one slender metatarsal, and 41 osteoderms of various sizes and shapes.”
Right mandible of Zhongyuansaurus junchangi. Image credit: Zhang et al., doi: 10.19800/ j.cnki.aps.2023037.
Zhongyuansaurus junchangi is characterized by a unique autapomorphy: at least five caudal armor plates arranged in a shingle-like pattern with a distinctive swallowtail shape.
“Additionally, it exhibits relatively slender mandibular bones compared to the more robust mandibles of advanced Ankylosaurinae,” the paleontologists said.
“The anterior tip of the coronoid process extends only to the last two alveoli, differing from Shamosaurus.”
“The distal caudal vertebrae are adorned with small osteoderms, and the humerus has a midshaft circumference-to-total-length ratio of 0.46, distinguishing it from Zhongyuansaurus luoyangensis.”
“The discovery of Zhongyuansaurus junchangi provides new insights into the evolution of ankylosaurs in the Lower Cretaceous strata of Ruyang and enhances the species diversity of the Ruyang dinosaur fauna,” the researchers concluded.
Their paper was published in the journal Acta Palaeontologica Sinica.
_____
Ji-ming Zhang et al. 2025. New ankylosaurid material from the Lower Cretaceous of the Ruyang Basin, Henan Province. Acta Palaeontologica Sinica 64 (1): 60-73; doi: 10.19800/ j.cnki.aps.2023037