Plant or Animal? Mysterious Fossils Defy Classification

One of the approximately 600-million-year-old fossils unearthed in China this organism was probably seaweed. It has a root-like holdfast to secure it to the sea floor, a conical stem and a crown of ribbon-like structures.
Zhe Chen

Strange fossils, including some that could be predecessors to modern animals, found in China shed new light on the evolution of large, complex organisms, and indicate that they may have diversified earlier than thought.

Researchers believe that the rocks containing these fossils, found in southern Anhui Provence, date between 635 million and 580 million years ago. The new types of organisms discovered in them include two that are fan-shaped, as long as 2 inches (5 centimeters), and resemble seaweed, as well as three other new types of organisms that are difficult to classify as animal or plant.

"Some of my colleagues are more leaning toward the animal interpretation," said study researcher Shuhai Xiao, a professor of geobiology at Virginia Polytechnic Institute and State University. "But my personal view is that we still don't know what they are."