Evolutionary consequences of dating the Yixian Formation

The Yixian Formation of northeastern China has yielded important new fossil s that are fuelling debates on the origin of angiosperms, on the early radi ation of birds and of mammals, and on the origin of feathers, Although thes e fossils provide a wealth of detailed anatomical information, knowledge of the absolute age of the Yixian Formation is crucial if we are to understan d their true evolutionary significance. The age of the Yixian Formation has been disputed, but recent evidence provides strong support for an Early Cr etaceous rather than a Late Jurassic age.