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Sixty-six million years ago, an asteroid impact near Mexico's Yucatan Peninsula ended the era of non-avian dinosaurs. But amid the global upheaval, some birds—including those that gave rise to modern ducks and geese—found refuge in the temperate conditions of Antarctica. Now in the journal Nature published article describing a nearly complete fossil skull Vegavis iaai – an ancient relative of modern waterfowl, which is 69 million years old.
Controversy surrounding fossils
First description Vegavis was done almost 20 years ago by Julia Clark of the University of Texas at Austin and her colleagues. They suggested that this bird was a primitive representative of modern (crown) waterfowl.
However, given the rarity of modern bird species found before the Cretaceous–Paleogene boundary, some researchers have questioned this classification. The new specimen helps resolve these doubts, as it contains anatomical regions not found in previous specimens, including a nearly intact skull.
Features of the structure of the skull
Doubts about the bird's identity have been largely dispelled by key features of its skull - in particular the structure of the beak and the structure of the brain, which are similar to modern waterfowl.
The specimen also shows powerful chewing muscles, which likely helped Vegavis dive and fish. This sets it apart from most modern waterfowl, but it resembles diving birds such as loons and grebes. These features of the skull, combined with other skeletal evidence, confirm that Vegavis moved in the water, pushing off with its feet to pursue prey – which is atypical for modern ducks and geese.
"This find highlights what Antarctica has to tell us about the early stages of the evolution of modern birds," said study co-author Patrick O'Connor, a paleontologist at Ohio University and director of the Department of Earth and Space Sciences at the Denver Museum of Nature and Science.
Late Cretaceous birds
Most bird fossils from this period found in other parts of the world are primitive in appearance. Furthermore, the sites where such fragile remains are preserved are rare, and the fragments found are often insufficient to determine their evolutionary relationships - this was the case with Vegavis until now
"And the few places where there is relatively rich Late Cretaceous fossil material, such as Madagascar and Argentina, reveal a whole world of strange, now extinct birds with teeth and long, bony tails that are only distantly related to modern species," O'Connor said.
"Something very different seems to have been happening in the southernmost regions of the Earth, especially in Antarctica."
The role of Antarctica in the evolution of birds
How Antarctica has shaped the development of modern ecosystems over millions of years remains a major scientific question. According to study co-author Matthew Lamanna of the Carnegie Museum of Natural History, Antarctica is a kind of “final frontier” in our understanding of life during the age of dinosaurs.
“This discovery beautifully demonstrates the power of scientific research and the important role that academic institutions play in studying the deep history of the Earth,” said Ohio University President Lori Stewart Gonzalez.
"This work not only expands our understanding of early bird evolution, but also highlights the invaluable contributions of the graduate and postdoctoral students who participate in these studies. It is through global expeditions like these – both in the field and in the laboratory – that we can better understand the dynamic changes our planet has undergone over millions of years."
Gonzalez also emphasized that such large-scale projects help prepare the next generation of scientists to collaborate and solve the most important questions about our world.
"It is through research like this that we are preparing the next generation of scientists who will advance science and find answers to the most complex questions concerning our planet," O'Connor concluded.
