Chinese and German scientists in southwest China's Guizhou Province claim they have discovered the world's earliest fossilized animals belonging to the Cambrian period.

Studies of the fossils, unearthed in Zhongnan village in the city of Zunyi, reveal that the "Cambrian explosion" was not as abrupt and dramatic as previously thought, said Professor Zhao Yuanlong of the Industrial University of Guizhou.

The fossils, believed to date back 535 million years, are in eight categories, including sponges, large bivalve arthropods, algae, echinoderms, and hemichordates.

Studies of the fossils show that there were no abrupt changes in the evolution of sponges during the Precambrian and Cambrian periods, said Zhao, who headed the Sino-German joint research team.

Therefore, he added, the Cambrian explosion theory, which considers the period the origin of the diversification of life on the planet as we now know it, needs to be rethought.

Dr. M. Stainer of the Berlin Industrial University and also the man who discovered the fossils, said that the fossil find at Zunyiis of great significance for research into the origin and evolution of early life.

The research project, which began in early 1998, was jointly sponsored by the China National Natural Science and the German Natural Science Fund.

The Zunyi fossils are believed to date back 1-2 million years earlier than fossils discovered in the mid 1980s in Chengjiang, about 100 kilometers from the Yunnan provincial capital of Kunming.

Fossils found in Poland in 1975 were thought at that time to be the earliest fossils belonging to the Cambrian period. But these newly discovered fossils are estimated to be 500,000 to one million years earlier.

An article explaining the significance of the finding will soon be published in the supplement of the latest issue of the Chinese periodical Paleontology Studies. (Xinhua)