GUIYANG, May 20 (Xinhua) -- Scientists from the Chinese Academy of Sciences have recently found a fossilized body piece of an extinct class of marine animal known as Cystoidea or cystoids in southwest China's Guizhou Province.

The fossil, that dates back some 400 million years, was discovered in Tongzi County while the scientists were studying a geological section in the area, according to the county government.

With an egg-shaped body, cystoids are echinoderms, marine invertebrates that existed during the Pleozoic Era, the Ordovician and Silurian Periods, and became extinct during the Devonian Period.

Guizhou boasts a rich store of prehistoric treasures. Fossils of various extinct invertebrate marine species have been discovered in the area. Tens of thousand of vertebrate fossils have also been found there.