From butterflies to blue whales, corals and worms, Earth is home to an incredible diversity of animals. How all of these animals evolved from earlier, simpler ancestors is one of the most exciting stories in the history book of life on our 4.5 billion-year-old planet.

A new study, published today in Science Advances, adds crucial information to this story. Led by Scott Evans, assistant curator of invertebrate palaeontology at the American Museum of Natural History, it draws on rare 567-million-year-old fossils to show animal evolution may have started far earlier than previously thought.

Ancient life on the seafloor

Long before life on land or even fish, Earth’s seafloor was home to large and complex animals.

Some of these soft-bodied and strange animals were shaped like pancakes. Others were more like soft tubes or spirals that pressed into the mud.

We call this time, from about 635 to 538 million years ago, the Ediacaran Period. Do animals from this period represent our ancient ancestors before the Cambrian explosion, which produced most of the basic groups of animals we know today? Or are they failed evolutionary experiments?

To help us answer these questions, we divide the Ediacaran fossil record into three broad chapters: the Avalon, White Sea and Nama assemblages. Each represents a distinctive community of Ediacaran animals that tend to appear in different times and environments.

These chapters help........

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