Paleontologists from the United States and Australia have discovered and described a new, nearly complete skull of Vegavis iaai, a foot-propelled diver bird species that lived in Antarctica during the latest Cretaceous, between 69.2 and 68.4 million years ago. The new fossil provides insight into the bird’s feeding ecology and exhibits morphologies that support placement among waterfowl within crown-group (modern) birds.
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Vegavis iaai. Image credit: Mark Witton.
Vegavis iaai was first discovered two decades ago by a research team led by University of Texas at Austin paleontologists.
At that time, the species was proposed as an early member of crown birds that was evolutionarily nested within waterfowl.
But crown birds are exceptionally rare before the end-Cretaceous extinction, and more recent studies have cast doubt on the evolutionary position of Vegavis iaai.
“Few birds are as likely to start as many arguments among paleontologists as Vegavis,” said University of the Pacific’s Professor Christopher Torres.
“This new fossil is going to help resolve a lot of those arguments. Chief among them: where is Vegavis iaai perched in the bird tree of life?”
The nearly complete skull of Vegavis iaai was collected during a 2011 expedition by the Antarctic Peninsula Paleontology Project.
Professor Torres and his colleagues generated a near-complete three-dimensional reconstruction of the new specimen.
The team’s analysis reveals a typical avian brain shape, supporting the placement of Vegavis iaai within the waterfowl family and as a close relative of ducks and geese.
However, the study also shows that the bird had a slender, pointed beak powered by enhanced jaw muscles, a feature that is less like other known waterfowls but more like diving birds.
“This fossil underscores that Antarctica has much to tell us about the earliest stages of modern bird evolution,” said Ohio University’s Professor Patrick O’Connor.
“Birds known from elsewhere on the planet at around the same time are barely recognizable by modern bird standards.”
“Moreover, most of the handful of sites that even preserve delicate bird fossils yield specimens that are so incomplete as to only give hints to their identity, as was the situation with Vegavis until now.”
“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.”
The study was published today in the journal Nature.
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C.R. Torres et al. 2025. Cretaceous Antarctic bird skull elucidates early avian ecological diversity. Nature 638, 146-151; doi: 10.1038/s41586-024-08390-0
