Researchers in China have identified a previously unknown species of mountain lizard in the upper Dadu River Valley within the Hengduan Mountains of Sichuan Province. Named Diploderma bifluviale, the lizard features a distinctive wheat-colored tongue and thrives in semi-arid shrublands at high elevations. This finding highlights the region's understudied biodiversity.
Starting in 2018, a team of researchers conducted extensive field surveys in the upper reaches of the Dadu River. During these expeditions, they encountered a population of lizards exhibiting unusual traits not observed in other known species of the Diploderma genus from the area. Detailed genetic testing and morphological comparisons confirmed that this was an entirely new species.
The scientists named it Diploderma bifluviale, referencing its discovery near the confluence of the Chuosijia and Jiaomuzu rivers. With this addition, Diploderma bifluviale becomes the 47th recognized species of Diploderma in China. The genus is distributed throughout East Asia and the northern Indochinese Peninsula, inhabiting various mountain environments.
Measuring 6-7 centimeters in body length, D. bifluviale is distinguished by its unique coloring and wheat-colored tongue, setting it apart from closely related species. It inhabits semi-arid shrublands and rocky, sun-exposed valleys at elevations between 2,100 and 2,500 meters. The habitat consists of small-leaved shrubs and scattered stones, providing effective camouflage for the reptile.
"This discovery highlights the understudied biodiversity of the upper Dadu River," the researchers wrote in their report. The study was published in the open-access journal ZooKeys (2025; 1251: 17, DOI: 10.3897/zookeys.1251.153705) by authors Fengjing Liu, Yayong Wu, Jindong Zhang, Guang Yang, Shuo Liu, Xue Chen, Jiang Chang, Qiang Xie, and Bo Cai. This finding demonstrates that even in relatively well-surveyed areas of China, new species continue to emerge.