A feathery four-winged dinosaur

The troodontids and dromaeosaurs are the dinosaur groups most closely related to birds. Anchiornis huxleyi from the Jurassic of China was thought to have been a stem-group bird — on the way to accumulating bird-like traits but retaining significant characteristics from earlier forebears. But the discovery of a new and spectacular specimen shows instead that it was a troodontid. As such, it is a very early member of that group (antedating Archaeopteryx) and exhibits a rich plumage, especially on the legs and feet. The early history of the Paraves (troodontids, dromaeosaurs and birds) was clearly one of much evolutionary experimentation and ferment, only now being revealed as new fossil discoveries emerge.