Goblet-shaped sea jelly relatives with miniature “arms.” A plump, legless creature resembling a sausage. Long, wormlike animals tipped with flat “holdfast” discs for anchoring to the seafloor.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.AdvertisementAdvertisementDuring the Cambrian explosion, animals with a wide range of bizarre structures and adaptations emerged. Some groups died out, but others eventually gave rise to modern animal groups such as chordates, crustaceans and mollusks. Because the Cambrian fossil record preserves so much animal diversity, scientists have long hypothesized that complex animal life didn’t yet exist during the Ediacaran.However, the fossils from China tell a different story. These boneless organisms fossilized as biofilm — they were rapidly buried and compressed between layers of rock, leaving behind two-dimensional impressions of their organic tissues. Animals’ entire bodies were preserved. Feeding structures, delicate limbs and even traces of internal organs, which are typically lost during fossilization, are still visible.For the first time, scientists have highly detailed examples of animals from the latter part of the Ediacaran. What an international team of researchers saw suggests that complex a …
