Animals may have evolved 200 million years earlier than thought

A modeling study in Science Advances suggests the first animals may have appeared 800–700 million years ago, up to 200 million years earlier than the oldest known animal fossils (574 million years). The authors combined analysis of Mongolia's Kheseen Biota microfossils with molecular clocks.

• Oldest animal fossils dated to about 574 million years ago
• New estimate pushes animal origins to 800–700 million years ago
• Kheseen Biota microfossils were well preserved but contained no animals
• Molecular clocks shifted the timeline back by roughly 200 million years