Duck ancestors roamed Earth with dinosaurs

Recent examinations of an Antarctica fossil found in 1992 have revealed evidence of a prehistoric avian species called Vegavis iaai that appears to be a cousin of today's barnyard poultry. The existence of the fossil thus means that birds and dinosaurs overlapped and that these birds must have survived the Cretaceous-Tertiary mass extinction event that included the disappearance of all other dinosaurs.

Scientists have long debated whether birds coexisted with the giant reptiles. Genetic researchers have theorized that, considering DNA sequence data, an overlap had to occur. Critics, however, have pointed to the paucity of fossils proving the theory.

The species was unearthed from computed tomography scans of the fossil--which uncovered new bones deep within the rock matrix--and recovery of latex peels made of the specimen just after its discovery in Antarctica in 1992. The partial skeleton embedded in the fossil is the most complete specimen from the Cretaceous period to be found to have an evolutionary relationship to a living bird group.

The fossil's fragility hampered earlier investigation. Earlier this year, the National Science foundation gave a grant to re-examine the fossil to Julia Clarke, an assistant professor in the marine, earth and atmospheric sciences department at N.C. State.

"We have more data than ever to propose at least the beginnings of the radiation of all living birds in the Cretaceous," Clarke said in a statement. "We now know that duck and chicken relatives coexisted with nonavian dinosaurs. This does not mean that today's chicken and duck species lived with nonavian dinosaurs but that the evolutionary lineages leading to today's duck and chicken species did."

Earlier this month, scientists at the University of Washington posted a paper theorizing that "The Great Dying," a mass species extinction that occurred several million years before the dinosaur extinction, was caused by global warming--not an asteroid.