The Chongqing Museum of Natural History began formal excavation Wednesday of a dinosaur fossil newly discovered at the shoal of the Jialing River in southwestern China's Chongqing Municipality.

Belonging to the Mamenxi dinosaur of the sauropod family, the dinosaur lived in the late Jurassic period about 130 million years ago.

According to Zhang Yihong, a research member with the museum, the dinosaur fossil, which is well preserved, is 18 meters long and the height of its back is 3.5 meters.

"Although the size of the dinosaur fossil is smaller than the Hechuan Mamenxi dinosaur, from the shape of the skeleton of the dinosaur we can judge that the age it lived should be earlier than the Hechuan Mamenxi dinosaur and the Jianshe Mamenxi dinosaur discovered in Zigong County, southwestern Sichuan Province," said Zhang.

"In this sense, the fossil discovered in Chongqing is of great significance to the study of the Mamenxi dinosaur and its evolution," said Zhang.

Experts evaluation shows that the 12 vertebras, four sacral vertebras, cervical vertebra and caudal vertebra of the dinosaur fossil are all quite intact. Possible fossil of teeth, pubic bones and fragments of the jaw bone were discovered at the nearby shoal.

"The fossil is quite intact as nearly 70 percent of the dinosaur bone is preserved," said Zhang.

As the site where the dinosaur fossil was discovered is not far from the Jialing River, Li Qinghua, vice curator of the local museum of natural history, said that they will expedite their excavation so that the whole fossil could be saved before the river goes up before this year's flooding season.

The Mamenxi dinosaur is named after a dinosaur fossil unearthed in 1957 in Hechuan City, Chongqing Municipality. The fossil, which is 22 meters long and the height of its back is 4 meters, is the largest and the most intact fossil ever discovered in Asia.

As a particular dinosaur species that lived in East Asia, the Mamenxi dinosaur bloomed in the late Jurassic period about 150 million years ago and became extinct in the Cretaceous period. TheMamenxi dinosaur, herbivorous and gregarious, is the animal species known for the longest neck that ever existed on the earth.

(Xinhua News Agency March 26, 2004)