BEIJING -- Chinese scientists have discovered new cyprinid fish fossils from the early and middle Miocene of the Lunpola Basin in Northwest China's Qinghai-Tibet Plateau. These findings indicate that fish diversity on the plateau was notably high between 18 and 15 million years ago.

The research team from the Institute of Vertebrate Paleontology and Paleoanthropology and the Institute of Hydrobiology, both under the Chinese Academy of Sciences, conducted detailed comparative studies on fossil specimens collected from the Lunpola Basin, which sits at an average elevation of 4,600 meters.

The fossils, recovered from the Chebuli and Lunbori sections within the basin, date back to around 15 million years and 16-18 million years, respectively.

After thorough morphological examination and comparison with modern fish specimens, researchers confirmed that these fossils belong to the family Cyprinidae and likely represent two new types distinct from other cyprinids known from the same period.

The Lunbori specimen is an incomplete spinous fin ray, characterized by serrations extending to the base of the fin ray. The Chebuli specimens include an incomplete skull fossil and an incomplete skeletal fossil.

These specimens show clear morphological differences from previously discovered Tibetan Cenozoic fish fossils, despite being found in close proximity both geographically and chronologically.

These new findings revealed that the hinterland of the Qinghai-Tibet Plateau during the late Paleogene and early Neogene periods should have hosted cyprinin fishes of greater diversity than today when the natural conditions are extremely harsh. This also indicates a warm-temperate paleoclimate suitable for their survival during that period.

East Asia is renowned for its exceptional freshwater fish diversity, making it one of the richest regions in the world in terms of aquatic biodiversity. The formation of the modern East Asian fish fauna, as well as some endemic East Asian groups, is generally considered to be closely related to major climatic events, according to Wu Feixiang, the corresponding author of the study which was published in the journal Acta Geologica Sinica.

The Qinghai-Tibet Plateau has a significant impact on the modern climatic environment of East Asia and the formation of its fish fauna. It not only serves as a "water source" for fish but also contributes to the Asian monsoon and the associated precipitation, which contribute to the exceptionally high fish diversity found in southern China.

Additionally, it has given rise to some endemic plateau fish groups. Therefore, research into the Cenozoic evolutionary history of fish on the Qinghai-Tibet Plateau is an important foundation for understanding the development patterns of East Asian freshwater fish fauna and its unique fishery resources.

The Cyprinidae is the largest family of modern freshwater fishes, and its distribution patterns and evolutionary history are also considered to be closely linked to the uplift of the Qinghai-Tibet Plateau and the formation of the Asian monsoon.