Imma Perfetto
Cosmos science journalist
The nearly complete fossilised skull of an ancient extinct bird might lay to rest controversial debate amongst palaeontologists about the first avians.
The extinct species, Vegavis iaai, lived in what is now Antarctica about 69 million years ago, during the late Cretaceous Period. The newly described fossil places the earliest known modern bird firmly as an early relative of ducks and geese (waterfowl).
“Few birds are as likely to start as many arguments among palaeontologists as Vegavis,” says Dr Christopher Torres of Ohio University and the University of the Pacific in the US, lead author of the Nature study describing the finding.
“This new fossil is going to help resolve a lot of those arguments. Chief among them: where is Vegavis perched in the bird tree of life?”
Vegavis was discovered 20 years ago from a partial skeleton, and initially was proposed to be an early member of modern birds, also known as crown clade (Aves), and specifically of waterfowl (Anseriformes).
However, this placement in the bird tree of life has remained controversial since.
Modern bird fossils are exceptionally rare prior to 66 million years ago, when an asteroid impact near Mexico’s Yucatán Peninsula triggered the extinction of all known non-bird dinosaurs, and more recent studies have cast doubt on the evolutionary position of Vegavis.
“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,” says Dr Patrick O’Connor of Ohio University and Denver Museum of Nature & Science, co-author of the study.
“Something very different seems to have been happening in the far reaches of the Southern Hemisphere, specifically in Antarctica.”
The new fossil, which was collected during an expedition to the Antarctic Peninsula in 2011, has something that all previous fossils of this bird lacked – a nearly complete skull.
It preserves skull features that are consistent with modern birds, specifically waterfowl, such as the shape of the brain and a long, narrow beak lacking teeth. It also reveals that Vegavis would have had powerful jaw muscles, used for overcoming water resistance while diving to snap up fish.
These features are consistent with other clues found in elsewhere in Vegavis’ skeleton which suggest the species used its feet to propel itself underwater in pursuit of fish and other prey.
Unlike modern waterfowl, this is a feeding strategy closer to birds such as grebes and loons.
“This fossil underscores that Antarctica has much to tell us about the earliest stages of modern bird evolution,” says O’Connor.
