CNN - Evidence of a worm-like creature about the size of a grain of rice has been uncovered in South Australia, and researchers believe it is the oldest ancestor on the family tree that includes humans and most animals.
The creature lived 555 million years ago.
"We thought these animals should have existed during this interval, but always understood they would be difficult to recognize," Evans said. "Once we had the 3D scans, we knew that we had made an important discovery."