An early web-footed diving bird that lived about 110 million years ago in China hints that all living birds might have had aquatic ancestors. The newly unearthed fossil also fills a key gap in the avian evolutionary record.
Gansus yumenensis was a foot-propelled diver like modern loons or grebes and about 25 centimetres long, says Matt Lamanna of the Carnegie Museum of Natural History in Pittsburgh, US. Although Gansus was not a direct ancestor of modern birds, it was the closest to modern birds yet found from the early Cretaceous.
The discovery offers new insight into the origins of modern birds, which remain a puzzle because fossils of their ancestors are scarce. Although many fossil birds are known from 125-million-year-old deposits in China's Liaoning province, the most common belonged to a now-extinct group called enantiornithines.
Gansus was much closer to modern birds as the oldest known member of the Ornithurae, a group that includes both modern birds and toothed marine birds that lived about 85 million years ago.
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http://www.newscientist.com/article/dn9341-feathered-fossils-suggest-aquatic-ancestry-for-birds.html
