Geoscientist Lida Xing was shopping at an amber market in Myitkyina, Myanmar in 2015 when he saw an unusual piece of amber. Trapped inside was a small object that the amber merchants thought was a sprig of leaves. But Xing thought something much more interesting was going on, so he decided to take a closer look. What he found could change our understanding of how feathers evolved.

Xing had discovered eight fully preserved vertebrae from a young, non-avian dinosaur called a coelurosaur. As an adult it would have been about the size of an ostrich, but this juvenile was still tiny enough to get trapped in tree sap and never escape. Feathers covered its tail, but at the tip they fluffed out in a pattern that suggested this animal may have had a fan-shaped tail. After Xing convinced the Dexu Institute of Paleontology to buy the amber, he and an international group of colleagues in China, England, and Canada examined it closely, using a number of imaging techniques that allowed them to generate 3-D reconstructions of the tail structure.

Chung-tat Cheung