A 69-million-year-old fossil of of a rare bird skull from Antarctica is enlightening scientists on the evolution of birdlife – and is among the earliest evidence of evolution across the globe.
The fossil belongs to Vegavis iaai, an extinct duck-like bird that lived during the Cretaceous period. It was collected during a 2011 expedition by the Antarctic Peninsula Palaeontology Project, and is one of very few bird skulls in existence from this time.
Vegavis is among the best-known bird species from this era, but research on this new skull is helping palaeontologists understand more about this extinct bird species – and also about birds living today. When the skull was discovered, it was identified as a close relative of modern ducks and geese. It therefore could be categorised in an evolutionary group called Anseriforms that encompasses both types of birds.
But these types of modern birds are exceptionally rare during the Cretaceous period. There has been speculation that Vegavis may be much more distantly related to bird lineages today.
‘Few birds are as likely to start as many arguments among palaeontologists as Vegavis,’ says lead author Dr Christopher Torres, a National Science Foundation postdoctorate fellow at Ohio University’s Heritage College of Osteopathic Medicine.
A new study published in the journal Nature shows that it should be kept in the Anseriformes group. This suggests that the earliest modern birds were evolving alongside non-avian dinosaurs. Researchers were surprised that it was closer to modern ducks than previously thought, due to its long spear-shaped beak. This distinctive beak shows the diversity of duck-like birds that roamed the earth during this period. Essentially, this is the earliest evidence of widespread evolution across the globe.
The new skull shows traits that are consistent with modern birds, particularly waterfowl. But unlike much of today’s waterfowl, the skull has traces of powerful jaw muscles for diving for fish against water resistance.
Non-bird dinosaurs were forced into extinction 66 million years ago, following an asteroid impact near the Yucatán Peninsula of Mexico. The early ancestors of today’s birds, however, managed to evade mass extinction. Antarctica may have become a refuge for these birds, thanks to its isolated environment and distance from the natural disaster.
Top image: An artist’s interpretation of Vegavis iaai. It is shown diving for fish in the shallow ocean off the coast of the Antarctic peninsula, with ammonites and plesiosaurs for company (credit: Mark Witton)
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