Paleontologists have announced the discovery of what they believe to be a new species of early-running Neonysikhia dinosaurs, part of the Jurassic Yangliao Biota in northern China.

Named Plasaurustinron, this newly identified dinosaur species lived in what is now China approximately 160 million years ago during the Jurassic period.

The ancient reptiles are part of what is known as the Yanliao Biota, a Jurassic ecosystem that included dinosaurs, mammals, amphibians, insects, lizards, and numerous plants.

“The Yanliao Biota is one of China’s most significant Mesozoic Lagerstättes, comprising fossil communities from the Jiulongshan and Tiaojishan formations, dating from 168 to 157 million years ago,” according to researchers from the China Academy of Sciences and Yunnan University.

“Overall, between 54 and 58 vertebrate species have been reported from the Yanliao Biota, which includes nine non-avian dinosaurs.”

“The Yanliao Biota preserves a large array of vertebrate material from various species, offering valuable insights into major paleontological milestones, such as the emergence of birds and the early evolution of mammals.”

“However, all non-avian dinosaurs found within the Yanliao Biota are small ceratopsians, while Ornithischia is represented by merely one species likely from the Jehol Biota.”

“This contrasts sharply with other contemporary Chinese terrestrial faunas, like the Shishugou and Shaximiao Faunas, where body sizes and taxonomic compositions are far more diverse.”

Plasaurustinron belongs to the group known as Neornithischia (New Ornithischians), a category of dinosaurs within the order Ornithischia.

First identified in 1985, Neornithischians are characterized by a thick layer of asymmetric enamel on the inner surfaces of their lower teeth.

“Neornithischia is a significant group of dinosaurs with early origins traceable to the central Jurassic region and possibly represented by several early extinction species such as Sanxiasaurus, Agirisaurus, and Hexine Rusaurus found in China,” said the paleontologist.

“Besides China, Neornithischian fossils have been reported from Jurassic regions in Eastern Europe, Scotland, and other geological periods and countries.”

“Neornithischia experienced rapid diversification into numerous species during the Cretaceous period.”

Well-preserved specimens of Plasaurustinron were discovered in the Tiaojishan formation in the Hebei Province of China.

“The fossil comprises nearly complete skeletons encased in slabs of brownish-red sandstone,” the researchers noted.

“The specimen retains most of its skull and complete post-cranial skeleton.”

According to scientists, Plasaurustinron was a small neornithischian dinosaur.

“The specimen’s total length is approximately 72.2 cm (measured from the rostral end of the skull to the caudal end of the last preserved vertebra), whereas the skull measures around 8 cm,” they mentioned.

The identification of this new species enhances our understanding of the biodiversity of the Yangliao Biota and the evolutionary relationships of early-running neornithischians.

“Phylogenetic analyses position Plasaurustinron at the base of Neornithischia, in proximity to Agirisaurus, the earliest neornithischian known,” the authors explained.

“This new species marks the first Neonysichian found within the Yangliao ecosystem and will help bridge the temporal and geographical gaps in the distribution of Neornithischia in China.”

“Additionally, the preserved remains of Plasaurustinron represent the second documented occurrence of ossified laryngeal structures among non-avian dinosaurs.”

“The laryngeal structures observed in Plasaurustinron suggest the presence of ossified laryngeal devices across other dinosaur species.”

In a manner resembling the arc shape found in modern birds, Plasaurustinron may have possessed bird-like vocalizations.

The discovery of Plasaurustinron is detailed in a paper published in the journal PeerJ.

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Y. Yang et al. 2025. A new neornithischian dinosaur from the Jurassic Tiaojishan formation in northern China. PeerJ 13:E19664; doi:10.7717/peerj.19664