A newly discovered species is now our oldest-known example of Ornithuromorpha, the evolutionary branch that hosts all living birds. This pushes back the origin of modern birds by nearly 6 million years. The new bird-old bird, named Archaeornithura meemannae, was announced in a Nature Communications paper published on Tuesday.
Archaeornithura meemannae lived some 130.7 million years ago (during the Early Cretaceous) in what's now the Sichakou basin of northeastern China. Until now, the oldest known member of the modern bird lineage was just 125 million years old.
Bird origins are important. We know with some certainty that birds descended from the dinosaurs, making them the last living remnants of the creatures that once dominated our planet. But not all dinosaurs had the privilege of spawning surviving bird lineages. In fact, some dinosaurs that did evolve into animals we'd call birds didn't make it: The branch Enantiornithes, which may have co-existed with Ornithurae at one point and are characterized by clawed wings and teeth, went extinct 66 million years ago.
So pinning down just when and how the Ornithurae emerged from earlier ancestors could tell us something about why they were the dinosaurs with staying power. But this specimen doesn't go quite early enough to do that.
This fossil has more in common with a modern bird than any found from such an early stage in their evolution, lead author Min Wang of the Chinese Academy of Sciences wrote in an e-mail to The Washington Post. In fact, it seems more bird-like than other, later members of Ornithuromorpha, which probably means these birds have an older-yet ancestor in common that's waiting to be discovered. With a common Ornithurae ancestor a few million years back, there'd be time for multiple branches of lineage to emerge, with some adapting modern qualities more quickly than others.
"The new bird is quite derived and has many advanced features of modern birds, and thus is far away from the transitional history of dinosaurs-birds," Wang said. "The most primitive bird of Ornithuromorpha is most likely from older deposits than what we discovered now."
While Wang says the reconstruction of the bird is largely based on imagination, he and his colleagues are confident based on the two specimens found -- which included nearly intact plumage and skeletal features -- that Archaeornithura meemannae was an adept flyer. Based on its location and the anatomy of its legs and feet, he believes it was a shorebird that waded into the water to feed.
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