Cretaceous fossils of early bird lineages are rare but important for understanding ecological shifts in bird evolution. One of the oldest known crown birds is Vegavis Iaai, a diving bird from Antarctica, dating to 69.2–68.4 million years ago. Its classification is debated. It was first thought to be related to ducks, but later studies suggest it might belong entirely to waterfowl or outside the bird group.
A new study by Ohio University found an important fossil of the oldest known modern bird, which lived in Antarctica when Tyrannosaurus rex ruled North America.
The fossil, a nearly complete 69-million-year-old skull, belongs to an extinct bird named Vegavis iaai. It was collected during a 2011 expedition by the Antarctic Peninsula Paleontology Project. The skull has a long, pointed beak and a unique brain shape not seen in other birds from the Mesozoic Era.
These features place Vegavis in the group of modern birds, marking the earliest evidence of successful evolutionary radiation across the planet.
Researchers say that the fossil discovery offers new insights into Vegavis iaai’s feeding habits and shows features supporting its classification as a waterfowl within modern birds.
“Few birds spark as much debate among paleontologists as Vegavis,” says lead author Dr. Torres. “This new fossil will help settle many arguments, especially about Vegavis’s place in the bird family tree.”
Dr. Julia Clarke and colleagues first reported Vegavis 20 years ago. They proposed it as an early member of modern birds within waterfowl. Modern birds were rare before the end-Cretaceous extinction, and recent studies have questioned Vegavis’s evolutionary position. The new study describes a nearly complete skull, which previous fossils lacked.
This new skull shows traits like the shape of the brain and beak bones consistent with modern waterfowl. Unlike most waterfowl today, the skull has powerful jaw muscles for diving and catching fish.
Vegavis has a bird-like beak without teeth, a smaller maxilla, and a brain with an enlarged cerebrum and downward-shifted optic lobes. The temporal fossa is well excavated and expansive, indicating that this bird had hypertrophied jaw musculature. The beak is narrow and pointed, and the mandible lacks retroarticular processes.
These skull features align with the rest of the skeleton, suggesting Vegavis used its feet for underwater propulsion, similar to birds like grebes and loons.
Dr. Patrick O’Connor, co-author on the study, professor at Ohio University, and director of Earth and Space Sciences at Denver Museum of Nature & Science, said, “This fossil underscores that Antarctica has much to tell us about the earliest stages of modern bird evolution.”
Journal Reference:
- Torres, C.R., Clarke, J.A., Groenke, J.R. et al. Cretaceous Antarctic bird skull elucidates early avian ecological diversity. Nature 638, 146–151 (2025). DOI: 10.1038/s41586-024-08390-0
Source: Tech Explorist
