Textbooks around the world will need changing to reflect the oldest known bird. A new species has knocked Archaeopteryx out of its former top spot.
A small, feathered beast called Aurornis xui, described in the latest issue of Nature, is now believed to be the first known bird.
"Our analyses indicate it as the most primitive bird known,” said co-author Andrea Cau, a vertebrate paleontologist at the Museo Geologico Giovanni Capellini in Italy. "It was a small feathered dinosaur that lived in what is now China about 160 million years ago. It looked like a ground bird, but with a long tail, clawed hands and toothed jaws.”
Cau and colleagues recently analyzed the bird’s remains, which were unearthed at the Tiaojishan Formation of Liaoning Province in northeastern China.
The name Aurornis xui is made up of the words Aurora (Latin for "daybreak”) Ornis (Greek for "bird”) and xui, in honor of Xu Xing, a well-known Chinese paleontologist who specializes in feathered dinosaurs and the non-avian dinosaur-to-bird transition.
The line between non-avian dinosaurs and birds blurs at the mid-to-late Jurassic period, but the researchers believe that both Aurornis and Archaeopteryx were more bird than non-avian dino. Prior to this study, there was some debate over whether Archaeopteryx, which lived 10 to 15 million years after Aurornis, was a bird. The authors of this latest report believe it was.
There is now a clear lineage leading from non-avian dinosaurs to birds, starting with the clade of dinosaurs called Maniraptora ("hand snatchers").
"The maniraptoran theropods are the animals most similar to Archaeopteryx and early birds, and thus are the best candidate as avian ancestors,” Cau said. "In particular, we found that the earliest birds were very similar to the earliest troodontids, a kind of maniraptorans.”