Scientists from Yunnan University in China have discovered 700 fossils at the Jiangchuan Biota, a site in southwest China that helps scientists understand the transition between the Precambrian supereon and the Phanerozoic. The fossils, which were discovered during the Cambrian Explosion, were found to be among chordates and bilaterians, the ancestors of all vertebrates, including humans. The discovery could help explain the origin of complex life in the fossil record, which may have been misrepresented due to missing evidence in fossil record. Most of the fossils are ancestors of modern invertebrates, but a few among them count as ancient ancestors of humans. This discovery closes a major gap in the earliest phases of animal diversification, with lead author Gaorong Li stating that many complex animals were present in the Ediacaran period, meaning they evolved earlier than previously demonstrated by fossil evidence.