How a Chinese fish fossil discovery rewrites the history of life's evolution - Salon

Paleontologists are having a field day over a recently discovered trove of fish fossils that could reset our understanding of human evolution.

The fossils date between 436 and 439 million years ago, during a known as the Silurian Period, in which Earth experienced some dramatic events (such as developing an ozone layer) that had big impacts on the evolution of life.

In general, scientists have relied on scraps and stray fossils of such creatures to formulate theories on how life arose on Earth during this era, but these new discoveries reveal in greater detail what creatures were like almost half a billion years ago.

It may be the oldest jawed ancestor of humans, pushing back the previous record by about 20 million years.

"Tens of thousands of fossils are known from China and Vietnam, but almost all of them are just heads — nothing has been known about the rest of their bodies — until now.".

These fossils lend weight to the "fin-fold theory," which describes how fish developed fins that separated and eventually evolved into legs.

"Only 20 years ago it was still believed that sharks [were] primitive and other jawed fish evolved from a shark-like archetype?