A fossil found in China suggests modern birds shed the long, bony tails of their dinosaur ancestors through a step-by-step process, rather than a sudden evolutionary transition as previously believed. The transition to a short, feathered tail was one of the most important steps in the evolution and survival of birds, the only living group of dinosaurs to survive a mass extinction event 66 million years ago. “The evolutionary assembly of the flight-adapted bird body plan encompasses some of the...