Chinese and British paleontologists discovered the well-preserved fossil along a forested lakeside in the country's northern Hebei Province.
"Eoconfuciusornis provides a new piece in the puzzle of the evolution from Archaeopteryx to more advanced birds," said study co-author Zhou Zhonghe, executive director of the Institute of Vertebrate Paleontology and Paleoanthropology in Beijing.
Etched in Stone
The fossil bird likely plunged into a lake 131 million years ago, where it drifted to the bottom and was quickly covered in sediment. Over time the animal became encased in mudstone.
The specimen's fully developed, modern-looking wings and symmetrically balanced tail feathers were etched into the stone in curved lines of black and brown.
"The brown and black may reflect the original colors, but these might alternatively have been the bright reds, blues, and yellows of modern birds," said study co-author Mike Benton, a paleontologist at the University of Bristol in the United Kingdom.
Lead author Zhang Fucheng, a professor at the Beijing institute, added: "Eoconfuciusornis was extraordinarily well preserved for the fossil to have contained such depth of detail."
The study appeared recently in the journal Science in China.
Awkward to Smooth
Archaeopteryx was likely an awkward flier, weighted down with a long bony tail, teeth, and other physical features of a dinosaur.
The newfound bird and a long lineage of descendants, which lived between 120 and 131 million years ago in the Cretaceous period, had developed a skeletal and muscle structure that provided more maneuverability and powered flight, Zhou said.
But Eoconfuciusornis and Archaeopteryx did share a limited ability to ascend from flat, low surfaces—an anatomical drawback that would have made both birds vulnerable to attack, Zhou said.
Eoconfuciusornis probably lived in trees and had claws to help it climb trunks and perch on branches, Zhou said.
It also likely glided across lakes to track and target fish, he added.
Xu Xing is a paleontologist at the Chinese paleontology institute who was not involved in the new study.
"The new discovery of Eoconfuciusornis adds to the remarkable diversity of the species known to be capable of flying or gliding in this part of the world 125 million years ago," Xu said.
In 2003 Xu discovered the 128-million-year-old fossil of the strange, four-winged dinosaur Microraptor gui, which he said probably could glide from tree to tree.
And earlier this year scientists unearthed the fossil of a miniature pterosaur that also soared across the same Cretaceous-period lakes and forests as Eoconfuciusornis.