NANJING, April 27 (Xinhua) -- A group of Chinese and American paleontologists said they have discovered an ancient fossil group of marine species dating back about 504 million years in Linyi City, east China's Shandong Province.

The fossil assemblage, named "Linyi Lagerstatte" by the researchers, consists of more than 35 extinct species living on the ocean floor, mainly arthropods, said Zhao Fangchen, a researcher from the Nanjing Institute of Geology and Paleontology, the Chinese Academy of Sciences.

A variety of spongia and vermicular life-forms were also found among the fossil group. The Linyi Lagerstatte is remarkable for its excellent preservation of arthropod limbs, eyes, and guts, and these well-preserved fossils promise to yield new anatomical data bearing on the early evolution of animals, according to Zhao who leads the research.

The animal group is believed to have existed on Earth right after the Cambrian explosion, a critical evolution period that led to the emergence of the ancestors of many modern organisms.

"The multi-category marine species of the Linyi Lagerstatte can offer not only a vivid portrayal of the thriving organisms at that time, but also an important window into the morphological disparity, community structure, and paleogeographic distribution of marine faunas following the Cambrian explosion," Zhao said.

The study has been recently published online in the journal National Science Review.