This paper reports chemical fossils characteristic of sponges that date back at least 635 million years ago, constituting the earliest evidence yet found for animal life. The sponges lived during the Marinoan glaciation, the last of the immense ice ages at the end of the Neoproterozoic. No evidence has been found for animal life during the earlier Sturtian glaciation.
- Gordon D. Love
- Emmanuelle Grosjean
- Roger E. Summons
