The Search for the Original Silly Goose in the Fossil Record

It’s taken decades, but scientists may have finally found Earth’s first fowl.It started in 1993 on Vega Island, a frigid, windswept rock off the Antarctic Peninsula. A mostly headless skeleton of a loon-size diving bird emerged from rocks that, at 68 million years old, predated the dinosaur extinction. The species, which scientists named Vegavis iaai, presented a puzzle: What bird was it a feather of?Nearly 20 years later, a 2011 Antarctic expedition turned up a bird skull that more recently was matched with Vegavis iaai. In an analysis published Wednesday in the journal Nature, researchers are sticking their necks out to suggest that the mysterious Antarctic avian is an ancient relative of today’s geese and ducks, and the oldest known modern bird.“It’s exactly the kind of thing we need to help fill in an evolutionary gap,” said Christopher Torres, a paleontologist at Ohio University and an author on the paper. But he conceded, “that’s also what makes it so incredibly controversial.”In the past few decades, Dr. Torres said, researchers looking at bird genomics suggested that some modern bird families — particularly waterfowl and game fowl — probably appeared before the asteroid impact that wiped out the non-avian dinosaurs. But before the discovery of Vegavis in the 1990s, no characteristic fossils had been identified, leaving a gap between molecular data and rocky physical evidence.The mixture of archaic and modern skeletal traits in the original Vegavis specimen also made it difficult to place, said Chase Brownstein, a paleontologist at Yale University who was not involved in the research. Some researchers suggested that Vegavis might have been one of several families of extinct Mesozoic birds — some with toothed bills and clawed wing-fingers — that didn’t survive the Cretaceous period extinction. Others believed it was a modern bird, closer to loons, grebes or geese.The skull found in 2011 helped breach this prehistoric logjam.The researchers of the new paper generated a near-complete three-dimensional reconstruction of the bird’s head. They found that Vegavis had the toothless beak and brain shape characteristic of modern birds, Dr. Torres said, as well as specific skull traits that they argue suggest the bird is closely related to modern waterfowl. But — and here’s the silly part — the skull is quite different from those of living ducks or geese. Its beak was long and pointed. It had large glands to remove salt from the body, and powerful jaw muscles that allowed the bird to snap its jaws quickly underwater.The entire skeleton points toward a bird that dove underwater after fish and propelled itself with powerful kicking legs, Dr. Torres said. That is unlike any modern water fowl, “and much more similar to what we see in modern loons and grebes.”Despite the bird’s loony body plan and head, the fine details of its skull — including its jaw and beak — show specific traits that suggest waterfowl, Dr. Torres said.While Dr. Brownstein called the discovery of the Vegavis skull “exciting,” he isn’t convinced that it’s enough to settle the debate over the animal’s identity — or to clarify when bird lineages like waterfowl appeared. But even the most conservative interpretation of the skull indicates that modern birds and their closest toothless relatives were extremely anatomically diverse at the end of the Cretaceous period, he said.Others are more enthusiastic.The fact that a bird with such modern features was around by the end of the dinosaurs’ reign suggests that other major lineages of living birds were likely present as well, said Gerardo Álvarez Herrera, a paleontologist with the Bernardino Rivadavia Natural Sciences Argentine Museum who was not involved in the study. It’s possible that further exploration will uncover “the ancestors of ostriches, fowls, neoaves and ducks that may have roamed alongside non-avian dinosaurs.”