Fossil of oldest known modern bird uncovered in Antarctica, offers new evolutionary clues

A 68-million-year-old Antarctic fossil revealed the oldest known modern bird, Vegavis iaai, a duck-sized diver with traits linking it to today’s waterfowl.

A fossil unearthed in Antarctica has provided evidence of the oldest known modern bird—a species closely related to today’s waterfowl and roughly the size of a mallard duck. According to a recent study published in Nature, this fossil offers a glimpse into the evolutionary past of birds, revealing crucial insights about their survival and adaptation.

A fossil found in Antarctica revealed Vegavis iaai as the oldest known modern bird.(Representational image/Pixabay)

A glimpse into the cretaceous era

The fossil, estimated to be around 68 million years old, belongs to Vegavis iaai, an extinct bird species that lived during the late Cretaceous period. This was the time when the fearsome Tyrannosaurus rex dominated North America, just before a massive asteroid impact triggered the mass extinction of the dinosaurs.

Unlike modern birds, many avian species of that era possessed unique characteristics, such as toothed beaks and elongated, bony tails. However, Vegavis was a duck-sized bird that likely shared ecological similarities with loons, according to Christopher Torres, an assistant professor of biology at the University of the Pacific and lead author of the study.

A skilled underwater hunter

Torres explained that Vegavis was a foot-propelled pursuit diver, using its legs to propel itself underwater while hunting for fish. One of the most fascinating aspects revealed by the new fossil was the bird’s jaw musculature, which was well adapted for snapping its mouth shut underwater—an ability seen today in loons and grebes.

“This bird was a foot-propelled pursuit diver. It used its legs to propel itself underwater as it swam, and something that we were able to observe directly from this new skull was it had jaw musculature associated with snapping its mouth shut underwater in pursuit of fish,” said Torres.

Challenging previous assumptions

Although Vegavis was first identified two decades ago, its classification as a modern, or crown, bird species faced scepticism. Previously, most modern bird fossils had been discovered in post-extinction layers, leading many researchers to believe that birds with modern traits only emerged after the asteroid impact 66 million years ago.

Patrick O’Connor, a professor of anatomical sciences at Ohio University and co-author of the study, highlighted that previous Vegavis fossils lacked a complete skull. The skull is crucial for identifying defining features of modern birds, such as a toothless beak and an enlarged premaxillary bone forming the upper beak.

Unlocking evolutionary secrets

Encased in rock dating back approximately 68.4 to 69.2 million years, the fossil displayed several modern characteristics, including a toothless beak.

The brain shape revealed by the fossil also bore similarities to modern birds, further supporting Vegavis’ classification within the group that includes all modern bird species. O’Connor described it as “the earliest member of this entire radiation that we see around us today, that consists of 11,000 bird species.”

However, not all features aligned perfectly with today’s waterfowl. For instance, the skull showed evidence of a slender, pointed beak with enhanced jaw muscles—a trait more commonly found in diving birds rather than in traditional waterfowl.