It’s taken many years, 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 A largely headless skeleton of a loon-size diving hen emerged from rocks that, at 68 million years outdated, predated the dinosaur extinction. The species, which scientists named Vegavis iaai, offered a puzzle: What hen was it a feather of?
Almost 20 years later, a 2011 Antarctic expedition turned up a hen 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 historic relative of right now’s geese and geese, and the oldest recognized trendy hen.
“It’s precisely the form 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.”
Prior to now few many years, Dr. Torres mentioned, researchers taking a look at hen genomics advised that some trendy hen households — notably waterfowl and recreation fowl — most likely appeared earlier than the asteroid influence 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 knowledge and rocky bodily proof.
The combination of archaic and trendy skeletal traits within the authentic Vegavis specimen additionally made it troublesome to position, mentioned Chase Brownstein, a paleontologist at Yale College who was not concerned within the analysis. Some researchers advised that Vegavis may need been one in every of 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 hen, 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 hen’s head. They discovered that Vegavis had the toothless beak and mind form attribute of contemporary birds, Dr. Torres mentioned, in addition to particular cranium traits that they argue recommend the hen is carefully associated to trendy waterfowl. However — and right here’s the foolish half — the cranium is sort of totally different from these of residing geese or geese. Its beak was lengthy and pointed. It had giant glands to take away salt from the physique, and highly effective jaw muscle tissues that allowed the hen to snap its jaws shortly underwater.
The complete skeleton factors towards a hen that dove underwater after fish and propelled itself with highly effective kicking legs, Dr. Torres mentioned. That’s in contrast to any trendy water fowl, “and rather more much like what we see in trendy loons and grebes.”
Regardless of the hen’s loony physique plan and head, the high quality particulars of its cranium — together with its jaw and beak — present particular traits that recommend waterfowl, Dr. Torres mentioned.
Whereas Dr. Brownstein known 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 hen lineages like waterfowl appeared. However even essentially the most conservative interpretation of the cranium signifies that trendy birds and their closest toothless family have been extraordinarily anatomically various on the finish of the Cretaceous interval, he mentioned.
Others are extra enthusiastic.
The truth that a hen with such trendy options was round by the tip of the dinosaurs’ reign means that different main lineages of residing birds have been possible current as properly, mentioned Gerardo Álvarez Herrera, a paleontologist with the Bernardino Rivadavia Pure Sciences Argentine Museum who was not concerned within the research. It’s attainable that additional exploration will uncover “the ancestors of ostriches, fowls, neoaves and geese that will have roamed alongside non-avian dinosaurs.”
