Feathered fossils discovered by researchers from the Institute of Vertebrate Paleontology and Paleoanthropology in Beijing, China represent the earliest known members of the clade that produced modern birds, according to research published in Nature Communications.
The fossils, which were found in northeastern China by paleontologists Min Wang and Zhonghe Zhou, push back modern bird lineage by a minimum of five million years, and possibly indicates that their roots can be traced back even farther, explained Science.
The birds appear to have belonged to a species of wading bird that was also a nimble flyer. The fossils had intact plumage that dated back to at least 130 million years ago. The fossils were said to be well preserved, and revealed anatomical features indicating that trails vital to the creature’s long-term success evolved earlier than previously expected.
“New bird fossils seem to come out every week now,” University of Edinburgh paleontologist Stephen Brusatte told Science, “and they are revolutionizing our understanding of bird evolution. But of all the new specimens, this is one of the most important found over the last decade.”
Filling in the fossil gap for modern birds
Birds originally started evolving from dinosaurs approximately 150 million years ago during the end of the Jurassic period, when a group of smaller meat-eaters first used their feathered wings to take flight. These flying dinosaurs eventually split into two distinct groups of birds, including the one that ultimately gave rise to modern avian species, the ornithuromorphs.
According to the authors, the new fossils represent the oldest record of ornithuromorphs found to date from the early cretaceous of China. The two skeletons were found at the Sichakou basin in Hebei province, and the new species was named Archaeornithura meemannae. They were 15 centimeters tall and had no feathers on its legs, suggesting that it had a wading lifestyle. Also, the size and shape of its bones indicated good aerial maneuverability.
“The new fossils fill the gap in time and also in anatomy,” said Science. “Each exquisitely preserved specimen has the telltale traits of a modern bird: fan-shaped tail feathers, highly fused bones at the ends of the wings, and the U-shaped wishbone familiar to anyone who has carved a roast chicken. The fossils even have a small projection on the front edge of their wings – known to boost maneuverability during flight – that is remarkably similar to that of today’s birds.”
“Furthermore, Archaeornithura had long legs and feet apparently adapted to wading in water, similar to those of today’s plovers, suggesting that modern birds arose in aquatic habitats,” the website added. The authors believe that the fossils reveal the origins of the same features that would ultimately allow modern birds to survive the Cretaceous extinction events.