Of the 21 or so generally accepted animal phyla, only one, the Ctenophora, has no fossil record1. The Phylum Ctenophora or comb jellies, are typically globular, swimming marine organisms, widely distributed in today's oceans. They are small, delicate, mostly planktonic animals of a gelatinous nature2 that were first considered to be coelenterates but later were recognized as a distinct group of phylum rank. We have now discovered the pyritized fossil remains of a small, globular, soft-bodied ctenophore. It comes from the Lower Devonian Hunsrück Slate of West Germany and provides the first tangible evidence for the existence of the group. Our discovery demonstrates that the basic ctenophore body plan has changed very little over the past 400 Myr and suggests that the origin of the phylum must extend even further back in time.