I spotted his post, and realized it was a major discovery: I study fossil invertebrates at the Spanish Research Council. When I contacted Haefner, he agreed to donate the fossil to London's Natural History Museum.

Working with colleagues in the U.S. and U.K., we determined that this was a 510 million-year-old relative of today's starfish and sea urchins. It is highly unique, new to science, and has only a partial skeleton. We named it Yorkicystis haefneri, after its finder.

Yorkicystis has revealed new information about how early life was evolving on Earth at a time when most of today's animal groups first appeared.

The Cambrian explosion

Yorkicystis lived during the "Cambrian explosion," 539 million to 485 million years ago. Before this time, bacteria and other simple microscopic organisms lived alongside Ediacaran fauna, mysterious, soft-bodied creatures that scientists know little about.

The Cambrian brought a huge proliferation of species that emerged from the seas. They included groups of organisms that would eventually dominate the planet and representatives of most of today's animal groups.