NANCHANG, July 23 (Xinhua) -- Archaeologists in east China's Jiangxi Province have finished cleaning 8-tonne dinosaur fossils found at a local construction site last March, according to local authorities.

The fossils, found in the city of Ganzhou, were preliminarily identified as belonging to the group Hadrosauridae, or duck-billed dinosaurs, said Han Fenglu, an associate professor at the China University of Geosciences (Wuhan) and leader of the research team. The fossils include parts of the skull, teeth, spine, limb bones and ribs.

The bone fossils are believed to be from at least three dinosaurs, based on their locations and sizes.

Hadrosauridae embryo fossils had previously been found in Ganzhou, but there has been no detailed ontogeny study of an adult fossil. The discovery is of great research value and will help us understand the evolution and regional distribution of Hadrosauridae in the late Cretaceous period, Han noted.

So far, archaeologists have found and named nine dinosaur species in Ganzhou. The city is also the world's only known concentrated area of fossilized dinosaur embryos.

The Cretaceous period began 145 million years ago and ended 66 million years ago. According to existing fossils, most dinosaurs in Ganzhou lived in the late Cretaceous period, which was very close to the date of the dinosaur mass extinction.

The study of dinosaur and dinosaur egg fossils in Ganzhou may help us understand more about the fifth mass extinction on Earth, according to Wang Xiaolin, a researcher from the Institute of Vertebrate Paleontology and Paleoanthropology under the Chinese Academy of Sciences.

As of April, China has named 338 dinosaur species based on bone fossils, according to the Paleozoological Museum of China. These Chinese dinosaurs lived during periods ranging from the early Jurassic to the late Cretaceous.