Researchers digging in what was once the bottom of a Chinese lake have found the fossils of a loon-like creature that suggests today's birds may have evolved from aquatic environments.
Gansus yumenensis lived 110 million years ago, had feathers and was a foot-propelled diver with webbed feet, according to an international group of researchers.
From an evolutionary standpoint, it is the most advanced bird from that era yet to be discovered, the researchers say. The bird would have resembled a modern loon, but was not closely related to the loon or any bird alive today, they say.
The researchers found up to 40 Gansus fossils preserved in mudstone rocks deposited in an ancient lake in northwestern China, at a site near the town of Changma, about 1,200 miles west of Beijing.
Gansus is the oldest known member of the lineage of Ornithurae, which are believed to have evolved between 140 million and 110 million years ago. They include modern birds and some of their extinct cousins.
In common with modern birds, Gansus has foot and ankle bones fused together, breast bones developed for flight and shorter backs and longer hips than more primitive bird species, the researchers say.
The findings were reported today in Science by researchers from the Chinese Academy of Geological Sciences, the Carnegie Museum of Natural History, the University of Pennsylvania, Dixie State College, Drexel University and the Natural History Museum of Los Angeles County.