Feathered dinosaurs of Liaoning

In 1996 Chinese paleontologists Ji Qiang and Ji Shuan announced Sinosauropteryx, a small dinosaur from the Yixian Formation of Liaoning Province in northeastern China. The fossil, about 1 m long with a long tail, was surrounded by a fuzz of filaments along the neck, back and tail. A fuller description by Chen Pei-ji, Dong Zhiming and Zhen Shuo followed in Nature in 1998. It was a compsognathid, a meat-eating dinosaur that was not a bird.¹³

Until then, feathers were known only in birds and in the debated Archaeopteryx. The Liaoning rocks, with volcanic ash that buried animals quickly in lakes, preserved soft tissue in exquisite detail. Many of the fossils come from quarries worked by local farmers around the village of Sihetun, near Beipiao. In 2010 Zhang Fucheng and colleagues examined tiny pigment bodies called melanosomes in the filaments and showed that the tail was banded with ginger and white. More dinosaur finds followed, including Caudipteryx, Microraptor and Yutyrannus, many with true feathers.¹²

The finds turned the bird-dinosaur link from an argument into a view backed by hundreds of specimens, and showed that feathers evolved before flight. Some dinosaurs wore feathers for display or warmth. The effect on the field was dramatic: artists and museums redrew their dinosaurs, and other feathered finds followed quickly, with Protarchaeopteryx in 1997, Caudipteryx in 1998 and Beipiaosaurus in 1999.¹