~575 million years agoReputable sourceWell documented
The First Animals: The Ediacaran Biota
On the timeline · around ~575 million years ago · Proterozoic
What happened
The Ediacaran biota — soft-bodied organisms like the pancake-shaped Dickinsonia, which crept across microbial mats on the seafloor — are the oldest known fossils of large, complex animals, living in the tens of millions of years before the Cambrian.
Why it matters
These enigmatic creatures represent the dawn of animal life, the first complex multicellular organisms in the fossil record.