Xinhua:Ancient bird skeleton points to arid past of Qinghai-Tibet Plateau

BEIJING, April 4 (Xinhua) -- Scientists have found a new species of sandgrouse in rocks dating back 6 to 9 million years in northwest China's Gansu Province, pointing to dry, arid habitats near the edge of the Qinghai-Tibet Plateau as it rose to its current extreme altitude.

The new species, found by researchers from the Institute of Vertebrate Paleontology and Paleoanthropology (IVPP) of the Chinese Academy of Sciences, has been named Linxiavis inaquosus, and fills a gap in the sandgrouse fossil record.

The fossil of the partial skeleton includes much of the body, such as the shoulder girdles, wishbone, bones from both wings, vertebrae, and part of a leg. Unfortunately, the head is missing, said researchers.

The discovery was recently published in the journal Frontiers in Ecology and Evolution.

"As the oldest fossil of a sandgrouse in Asia and the most complete fossil known from the group, the new skeleton provides a key link in expanding our understanding of the evolution of the sandgrouse living in China today, as well as the ecosystem associated with the Qinghai-Tibet Plateau and the species that live only there," said Li Zhiheng, first author of the study.

Sandgrouse are a group of 16 species of birds related to pigeons that live in some of the most arid areas across Europe, Asia, and Africa. The association between sandgrouse and dry environments has helped scientists determine that the area next to the Qinghai-Tibet Plateau was equally arid when Linxiavis inaquosus lived during the period known as the late Miocene.

Most people would probably think of the Qinghai-Tibet Plateau, with its high elevation, low oxygen levels, and harsh sun as one of the last places to be invaded by a group of animals. "But in this case, our fossil suggests that sandgrouse might have quickly adapted to the dry, mountainous plateau millions of years ago," said the coauthor Thomas A. Stidham.

Importantly, this fossil is from the time period known as the late Miocene when the Qinghai-Tibet Plateau was continuing to rise rapidly in altitude and changing the climate of central Asia with an increase in aridity, along with a strong monsoon season, said scientists.

This fossil was found at over 2,000 meters above sea level. That elevation is far greater than where all species of sandgrouse, except for the specialized Tibetan Sandgrouse, live today.

Despite the elevation and arid conditions, other fossils from the area show that the ecosystem was quite diverse, said Stidham.

If you were on the edge of the plateau where the fossil is some 6 million years old, it would have looked quite like a nature documentary about the savannas in Africa, with the horizon filled with extinct relatives of hyenas, elephants, rhinos, pigs, antelopes, horses, ostriches, vultures, falcons, and of course now, sandgrouse, Stidham said.

"We are discovering many fossil birds in this area that help us to understand the relationships between the plateau, climate change and biodiversity. We're likely to keep uncovering more unusual and amazing bird fossils," Li added.


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