Palaeontologist Xing Xu bends low over a beautifully preserved specimen of the ancient bird species Sapeornis, entombed in a glass museum cabinet in Shandong Province, China. The bird's spindly legs stretch as if it were about to stride forward, even though the creature has been dead for more than 110 million years. From its chicken-sized body juts a fine neck, a delicate skull and the clear imprint of a long, jaunty tail feather — something never seen before in this species.

Sapeornis is one of hundreds of plumed specimens pouring out of fossil beds in China — most notably out of the rock formations in Liaoning Province, northeast of Beijing. Some of the Liaoning fossils are the earliest known birds. Others are feathered dinosaurs, the group that spawned birds millions of years before the age of Sapeornis. Together, they are among the most important finds in dinosaur palaeontology in the past century.

Xu is at the centre of that bonanza. He is “the go-to man in China for anything people want to know about dinosaurs”, says Paul Barrett, who studies dinosaurs at the Natural History Museum in London and first met Xu in the 1990s, when both were graduate students. Xu, who is based at the Institute of Vertebrate Paleontology and Paleoanthropology (IVPP) in Beijing, has named 60 species so far — more than any other vertebrate palaeontologist alive today. And he is only 43 years old.

In describing the flock of feathered fossils, Xu has helped to show that birds arose from dinosaurs, ending decades of debate. Along the way, he has shed light on the origins of feathers and flight. And he has bucked 150 years of received wisdom by declaring that the fabled genus Archaeopteryx is not the oldest known bird, but rather belonged to a group of dinosaurs removed from the avian line1. “He has patience and persistence — and an audacity when scientific evidence calls for it,” says Zhe-Xi Luo, who studies fossil mammals at the University of Chicago in Illinois.