Ancient webbed masters

Newly unearthed fossils of a 110-million-year-old species bolster the notion that all modern birds evolved from aquatic ancestors.

Fragmentary fossils of Gansus yumenensis collected earlier had suggested that it was a wading bird similar to today’s sandpipers, says Jerald D. Harris, a paleontologist at Dixie State College in St. George, Utah. The new specimens (one shown in inset) from northwestern China, which together include all the bird’s bones except its skull and upper neck, informed this artist’s sketch. The bird’s shape and its webbed feet indicate that the creature was a foot-propelled diver like modern loons. Features of some bones establish G. yumenensis as the oldest known ancestor of modern birds, Harris and his colleagues assert in the June 16 Science.