Scientists have unearthed in southeastern China the fossil of a quail-sized bird that lived about 150 million years ago during the Jurassic Period and possessed surprisingly modern traits, a discovery that rewrites the history of avian evolution.

The bird has a short tail ending in a pygostyle, an important aerodynamic innovation moving the center of mass forward toward the wings.

This discovery extends the timeline for the evolution of key bird features by millions of years. “Previously, the oldest record of short-tailed birds is from the Early Cretaceou