Hadrosaur fossil: It is the most complete of all those unearthed in Inner Mongolia in 20 years. [Photo provided to China Daily]

A rare well-preserved hadrosaur fossil has been unearthed in the Inner Mongolia autonomous region and is expected to be of huge value for research into how the species evolved, Chinese archaeologists said.

More than 90 percent of the bones of the animal were intact, including the head, cervical vertebrae, limbs and a complete tail-bone. It is the most complete dinosaur fossil unearthed in Inner Mongolia in 20 years.

The fossil was first dis-covered in 2012 in Urad Back Banner, in the north-west part of the region. Excavation started in June 2013.

More than 300 fossil bone fragments were excavated at the site, weighing 1 metric ton altogether, said Tan Lin, an engineer at the Longhao Geological Institute of Paleontology in Inner Mongolia.

Chinese researchers said the fossil structure of the hadrosaur was about 8 meters long, 1 meter wide and 5 meters tall. It was a mature dinosaur that lived 80 million years ago.

Ten workers are restoring the fossil in a storehouse in Chengguan town, Bayannur city. The work began in May this year and is expect-ed to end in October.

Such a complete dinosaur fossil is a very rare find, said Xu Xing, a researcher at the Institute of Vertebrate Paleontology and Paleoanthropology under the Chinese Academy of Sciences.

It will greatly inform research into the evolution of the hadrosaur species and biology in the Rehe area, he said.

Archaeologists also found fossils of other plants and living organisms in the Rehe area, which will prove invaluable in future research.