It’s taken a long time, however scientists might have lastly discovered Earth’s first fowl.
It began in 1993 on Vega Island, a frigid, windswept rock off the Antarctic Peninsula. A largely headless skeleton of a loon-size diving chicken emerged from rocks that, at 68 million years previous, predated the dinosaur extinction. The species, which scientists named Vegavis iaai, offered a puzzle: What chicken was it a feather of?
Almost 20 years later, a 2011 Antarctic expedition turned up a chicken cranium that extra not too long ago was matched with Vegavis iaai. In an evaluation revealed Wednesday within the journal Nature, researchers are sticking their necks out to recommend that the mysterious Antarctic avian is an historical relative of in the present day’s geese and geese, and the oldest identified fashionable chicken.
“It’s precisely the sort of factor we have to assist fill in an evolutionary hole,” mentioned Christopher Torres, a paleontologist at Ohio College and an creator on the paper. However he conceded, “that’s additionally what makes it so extremely controversial.”
Up to now few a long time, Dr. Torres mentioned, researchers chicken genomics prompt that some fashionable chicken households — notably waterfowl and sport fowl — in all probability appeared earlier than the asteroid affect that worn out the non-avian dinosaurs. However earlier than the invention of Vegavis within the Nineties, no attribute fossils had been recognized, leaving a spot between molecular information and rocky bodily proof.
The combination of archaic and fashionable skeletal traits within the unique Vegavis specimen additionally made it troublesome to put, mentioned Chase Brownstein, a paleontologist at Yale College who was not concerned within the analysis. Some researchers prompt that Vegavis might need been one in all a number of households of extinct Mesozoic birds — some with toothed payments and clawed wing-fingers — that didn’t survive the Cretaceous interval extinction. Others believed it was a contemporary chicken, nearer to loons, grebes or geese.
The cranium present in 2011 helped breach this prehistoric logjam.
The researchers of the brand new paper generated a near-complete three-dimensional reconstruction of the chicken’s head. They discovered that Vegavis had the toothless beak and mind form attribute of recent birds, Dr. Torres mentioned, in addition to particular cranium traits that they argue recommend the chicken is intently associated to fashionable waterfowl. However — and right here’s the foolish half — the cranium is kind of totally different from these of residing geese or geese. Its beak was lengthy and pointed. It had massive glands to take away salt from the physique, and highly effective jaw muscle tissue that allowed the chicken to snap its jaws shortly underwater.
The complete skeleton factors towards a chicken that dove underwater after fish and propelled itself with highly effective kicking legs, Dr. Torres mentioned. That’s not like any fashionable water fowl, “and far more just like what we see in fashionable loons and grebes.”
Regardless of the chicken’s loony physique plan and head, the effective particulars of its cranium — together with its jaw and beak — present particular traits that recommend waterfowl, Dr. Torres mentioned.
Whereas Dr. Brownstein referred to as the invention of the Vegavis cranium “thrilling,” he isn’t satisfied that it’s sufficient to settle the talk over the animal’s id — or to make clear when chicken lineages like waterfowl appeared. However even probably the most conservative interpretation of the cranium signifies that fashionable birds and their closest toothless relations have been extraordinarily anatomically numerous on the finish of the Cretaceous interval, he mentioned.
Others are extra enthusiastic.
The truth that a chicken with such fashionable options was round by the top of the dinosaurs’ reign means that different main lineages of residing birds have been probably current as nicely, mentioned Gerardo Álvarez Herrera, a paleontologist with the Bernardino Rivadavia Pure Sciences Argentine Museum who was not concerned within the research. It’s potential that additional exploration will uncover “the ancestors of ostriches, fowls, neoaves and geese that will have roamed alongside non-avian dinosaurs.”
