Newly Discovered Permian Herbivorous Tetrapod Species in China

Paleontologists have unveiled a significant discovery in the field of paleontology with the identification of a new genus and species of mid-sized pareiasaur, named *Yinshanosaurus angustus*. This species was unearthed from two fossilized specimens discovered in China in 2018, contributing valuable insights into the biodiversity of the Late Permian period, which spanned from approximately 259 to 254 million years ago.

The specimens were excavated from distinct geological formations in China, specifically from the lower part of the Sunjiagou Formation near Zhangjiagetuo village in Baode County, and from the Naobaogou Formation, near Qiandian village in Baotou City, Nei Mongol. According to Dr. Jian Yi and Jun Liu from the Institute of Vertebrate Paleontology and Paleoanthropology at the Chinese Academy of Sciences, *Yinshanosaurus angustus* is notable for having the narrowest skull among the known pareiasaurs, with its skull length measuring more than twice its width at the lateral edges of the cheeks.

The discovery is particularly significant as it represents the first complete cranial and articulated postcranial details of Chinese pareiasaurs, enhancing the understanding of this herbivorous clade of tetrapods. Dr. Yi emphasized that pareiasaurs were prominent primary consumers within several terrestrial tetrapod faunas, including the Late Permian fauna of northern China. The fossil record indicates that pareiasaurs had a widespread distribution, with fossils found across Africa, Europe, Asia, and South America, suggesting their ecological success during the Permian.

The findings were published in the journal *Papers in Palaeontology* on June 30, 2025, and the authors assert that this new species sheds light on the evolutionary relationships among pareiasaurs. The study provides a broader context for the survival and adaptation strategies of these organisms, especially considering they were victims of both the Late Capitanian and the end-Permian mass extinction events.

Dr. Richard Smith, a paleontologist at the University of California, Berkeley, commented on the significance of this discovery, stating, "Every new fossil adds a piece to the puzzle of early tetrapod evolution, and *Yinshanosaurus angustus* offers critical insights into the lifestyle and ecological roles of pareiasaurs during a tumultuous time in Earth's history."

The identification of *Yinshanosaurus angustus* not only contributes to the understanding of the Permian biodiversity but also invites further exploration into the paleobiological implications of this group. The information gleaned from this research may also assist in understanding the adaptive strategies of terrestrial vertebrates leading up to the mass extinctions that shaped the course of life on Earth. As the field of paleontology continues to evolve with new discoveries, the implications of *Yinshanosaurus angustus* could influence future studies on the resilience and adaptability of ancient species in the face of environmental changes.

The research team plans to continue their investigations in the region, hoping to uncover additional specimens that could provide further insights into the ecology and evolution of pareiasaurs and their environment during the Permian period.