Newfound fossils from a site in southwestern China, preserved in exquisite detail, offer a peek at a time in Earth’s distant past called the Ediacaran (635 million to 542 million years ago). The discovery suggests that complex animals — perhaps even ancestors of all vertebrates — were around millions of years earlier than once thought.
A few types of creatures were previously known from the Ediacaran, but the evolution of complex animal life has long been associated with the Cambrian, a later period from 542 million to 488 million years ago when fauna diversity and complexity were booming.