Chinese scientists have announced they have discovered chaetognath fossils dating back about 530 million years, according to the US magazine, Science, published Friday.
The discovery by Chen Junyuan, researcher of the Institute of Geology and Paleontology, a branch institute of the Chinese Academy of Sciences in Nanjing city, has pushed the origin of chaetognath back about 200 millions years and provided additional proof for the theory that diversity of modern life-forms could be traced back to a biological eruption in the Cambrian period (500 million to 540 million years ago).
The fossils, found by Chen and student Huang Diying, have been well preserved in the natural environment and each part of the chaetognaths can be clearly identified.
The chaetognath, usually called the arrow worm, is a phylum of the modern animal kingdom. There had been no major changes in its body and internal structure even though it had existed for millions of years, said Chen.
Prior to this discovery, the earliest chaetognath fossil was dated back to the Carboniferous period, approximately 290 million to 350 million years ago.
Chen said that after this discovery, 12 out of the total 35 phyla of modern animal life forms had been proven to have appeared in the Cambrian period, in accordance with the deduction that modern life diversity originated in that period.
(Xinhua News Agency October 4, 2002)
