An artist’s impression of Vegavis iaai, an ancestor of modern waterfowl – credit: Mark Witton / SWNS
A modern-looking diving bird was living somewhere in Antarctica when a massive asteroid struck the Earth and caused the dinosaurs to go extinct.
But unlike the dinosaurs, this early ancestor of today’s waterfowl survived that mass extinction event, and a nearly complete skull has now been recovered by a special paleontological project on the southern continent.
The animal is called Vegavis iaai—a Late Cretaceous diving bird which lived at the same time that Tyrannosaurus rex was dominating North America.
The skull exhibits a long, pointed beak and a brain shape unique among all known birds previously discovered from the Mesozoic Era—the epoch stretching from 252 to 66 million years ago, and comprising the Triassic, Jurassic, and Cretaceous Periods.
Researchers say the features place Vegavis in the group that includes all modern birds, representing the earliest evidence of a now widespread and successful evolutionary radiation across the planet.
Assistant Professor of Biology Chris Torres from the University of the Pacific acquired the fragments of the animal’s skull from a geology sample obtained during a 2011 expedition by the Antarctic Peninsula Paleontology Project.
Meticulously extracted and scanned into a 3D rendering, Torres said it was like trying to complete a 3D jigsaw puzzle without having a box to use as a reference.
“The pieces that are left, some of them are torn in half, some of those are missing pieces. Even then—you don’t know the picture on the box, right?” he told the Univ. of the Pacific press. “You know what other pictures on other boxes look like, and you’re using those to predict what this one looked like. I think it scratches the same itch a jigsaw puzzle does, but the stakes are much higher.”
The professor, who recently published an analytical study on the skull, added that the scale of the discovery is likely to trigger sizeable debates about where it fits in the story of modern birds.
Professor Christopher Torres at University of the Pacfic, and lead author on the discovery – credit: Ben Spiegel, UoP
“Few birds are as likely to start as many arguments among paleontologists as Vegavis,” he said. “Chief among them: where is Vegavis perched in the bird tree of life?”
Vegavis was first reported 20 years ago by study co-author Dr. Julia Clarke, of the University of Texas, Austin, and several colleagues. At that time, it was proposed as an early member of modern birds that was evolutionarily nested within waterfowl.
But modern birds are exceptionally rare before the Cretaceous extinction, and more recent studies have cast doubt on the evolutionary position of Vegavis. Several traits—including the shape of the brain and beak bones—are consistent with modern birds, specifically waterfowl.
Unlike most of today’s waterfowl, the research team says the skull preserves traces of powerful jaw muscles useful for overcoming water resistance while diving to snap up fish. It also leans more towards the feeding patterns of today’s grebes and loons rather than that of ducks or geese, as the features of its feet are more consistent with underwater propulsion.
Antarctica may have served as a refuge, protected by its distance from the turmoil taking place elsewhere on the planet and enriched by a temperate climate with lush vegetation.
“This fossil underscores that Antarctica has much to tell us about the earliest stages of modern bird evolution,” said professor at Ohio University and co-author Patrick O’Connor.
He says birds known from elsewhere on the planet at around the same time are “barely recognizable” by modern bird standards.
“And those few places with any substantial fossil record of Late Cretaceous birds, like Madagascar and Argentina, reveal an aviary of bizarre, now-extinct species with teeth and long bony tails, only distantly related to modern birds.”“Something very different seems to have been happening in the far reaches of the Southern Hemisphere, specifically in Antarctica.” Antarctica Yields Intact Skull — An Ancestor of Today’s Waterfowl That Survived Dinosaur Extinction
