NATURE COMMUNICATIONS, WANG ET AL.Two 130.7-million-year-old partial skeletons of Archaeornithura meemannae, a newly discovered species of ancient six-inch-tall wading bird found in siltstone slabs in northeastern China, represent the oldest known ancestor of modern birds, predating the previous record-holder by almost 6 million years, according to a study published this week (May 5) in Nature Communications.
After birds began to evolve separately from dinosaurs at the end of the Jurassic period (around 150 million years ago), two groups of species developed. The Enantiorinthes, which had teeth and clawed wings and did not fly well, went extinct 66 million years ago, while the Ornithuromorpha evolved into modern birds. Previously, the oldest known ornithuromorph fossil was dated to 125 million years ago.
In the new study, scientists from the Chinese Academy of Sciences, the Tianyu Natural History Museum of Shandong, China, and Macquarie University in Australia identified the fossils in the stone slabs from the Sichakou basin of the Hebei province as belonging to an older species with features present in modern birds. The birds were most likely good fliers, with such features as overlapping wing feathers that would help to create lift, a tuft of feathers on the front edge of the wings, present in modern kestrels, which increases maneuverability during flight, and similar bone structure to modern birds. The rest of the birds’ bodies were also covered in feathers, including a head crest and a fan-shaped tail, but the legs were bare, suggesting that A. meemannae was most likely a wading shorebird.
“The feathers are really beautiful. It is incredible how they were preserved so well for 130 million years,” study coauthor Min Wang of the Chinese Academy of Sciences told The Guardian.
However, since later specimens are in some ways less similar to modern birds than the new species, there is most likely an even older ancestor yet to be discovered. “The most primitive bird of Ornithuromorpha is most likely from older deposits than what we discovered now,” Wang told The Washington Post.