A newly unearthed 69-million-year-old fossil is shaking up long-standing debates amongst paleontologists about when trendy birds emerged. The invention of a just about whole cranium from the extinct chook Vegavis iaai means that the ancestors of lately’s birds coexisted with dinosaurs ahead of the notorious Chicxulub impactor burnt up 75% of Earth’s species 66 million years in the past. However the in finding raises even larger questions—used to be Vegavis an early waterfowl, or one thing totally other?
The Fossil That May just Settle a A long time-Previous Debate
For years, scientists have debated whether or not trendy birds developed ahead of or after the asteroid affect that ended the Cretaceous Length. The argument hinges on a unmarried query: did any of the birds we see lately descend from creatures that shared the arena with T. rex?
In 2005, paleontologists first recognized Vegavis iaai in response to a fossil present in Antarctica, courting again 68 million years. However that specimen used to be lacking maximum of its cranium, making it tricky to verify whether or not it in reality belonged to trendy birds or used to be merely an in depth relative.
Now, a brand new fossil came upon in 2011 and analyzed in a contemporary learn about printed in Nature seems to give you the lacking hyperlink. The well-preserved cranium unearths key bird-like options, together with a protracted, toothless beak and an enlarged forebrain—characteristics that fit trendy birds.
“This new fossil goes to assist unravel a large number of the ones arguments,” says Christopher Torres, the learn about’s lead writer and a paleontologist on the College of the Pacific. “Leader amongst them: the place is Vegavis perched within the chook tree of existence?”
A virtual reconstruction of Vegavis iaai’s cranium, finished following high-resolution micro-computed tomography of a fossil-bearing concretion came upon on Vega Island.Credit score…C. Torres and J. Gronke
Waterfowl or One thing Else? The Debate Heats Up
Even with this new fossil proof, paleontologists are divided over what sort of chook Vegavis in reality used to be. Early research steered that it used to be ancestor of geese and ducks, however the brand new cranium suggests an overly other way of life.
“So this chook used to be a foot-propelled pursuit diver,” Torres explains. “It used its legs to propel itself underwater because it swam, and one thing that we have been ready to look at immediately from this new cranium used to be it had jaw musculature [that] used to be related to snapping its mouth close underwater in pursuit of fish.”
That description sounds extra like loons and grebes—trendy diving birds—than geese or ducks. And a few scientists don’t seem to be satisfied that Vegavis belonged to the gang that finally gave upward thrust to trendy waterfowl.
“This fossil is thrilling,” says Chase Brownstein, an evolutionary biologist at Yale College, “however I’m no longer but satisfied it manner Vegavis used to be a duck ancestor.”
Antarctica: A Hidden Sanctuary for Early Birds?
Probably the most greatest implications of the Vegavis discovery is what it suggests about Antarctica all over the past due Cretaceous Length. These days, it’s a frozen desolate tract, however 69 million years in the past, it used to be a lush, temperate area teeming with plants.
Some researchers now speculate that Antarctica can have equipped a shelter for early birds, letting them continue to exist the cataclysmic asteroid affect that burnt up their dinosaur family members.
“Antarctica is in some ways the general frontier for our figuring out of existence all over the Age of Dinosaurs,” says Matthew Lamanna, a paleontologist on the Carnegie Museum of Herbal Historical past.
With extra fossils nonetheless ready to be came upon underneath the ice, the tale of ways birds survived whilst the dinosaurs perished is a ways from over.
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