Paleontologists Discover Fossil of the Oldest Known Modern Bird—but It Raises More Questions Than It Answers
The fossil suggests that modern birds evolved before the dinosaur-killing asteroid, perhaps in Antarctica
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The Chicxulub impactor smashed into Earth, wiped out around 75 percent of our planet’s animals and ended the Cretaceous Period 66 million years ago. The only dinosaur species to survive were birds.
Paleontologists have been arguing whether modern birds developed before or after the infamous asteroid for decades. Now, a team of researchers has analyzed a 69-million-year-old fossil belonging to the long-extinct bird Vegavis iaai that could put the discussion to rest.
As detailed in a study published Wednesday in the journal Nature, the researchers claim the fossil to be the oldest known modern bird and thus definitive proof that modern birds developed alongside dinosaurs. The contentious prehistoric bird, however, has also raised many more questions, namely in regard to its potential relation to waterfowl like duck and geese.
"Few birds are as likely to start as many arguments among paleontologists as Vegavis," Christopher Torres, lead author on the study and a paleontologist at the University of the Pacific, says in a statement. "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?"
Julia Clarke, a co-author of the study and a paleontologist from the University of Texas at Austin, first identified Vegavis along with colleagues 20 years ago, per the statement, from a 68-million-year-old fossil discovered in Antarctica. The fossil was missing most of its skull, however, which made it difficult to confirm any claims of it being an early modern bird.
In 2011, another Antarctic expedition unearthed the newly-described and almost fully intact 69-million-year-old fossil. The specimen’s skull made it clear that the animal had a long toothless beak and an enlarged forebrain—just like the one that exists in modern birds.
“Based on the neuroanatomy, it looks a lot like a living bird,” Amy Balanoff, an evolutionary biologist at Johns Hopkins University who was not involved in the study, tells Science’s Rodrigo Pérez Ortega. Additionally, its "maxilla [a beak bone] is tiny, which is exactly what we expect from modern birds," Torres tells Live Science’s Kristel Tjandra.
Torres and his colleagues argue that these two features also point to Vegavis being an early relative of waterfowl like modern ducks and geese. It’s a claim that had also been tentatively suggested about the earlier discovery of the head-less fossil—and one that hasn’t gone down smoothly in the paleontology community.
“So 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 [that] was associated with snapping its mouth shut underwater in pursuit of fish,” Torres explains to CNN’s Katie Hunt. “And that is a lifestyle that we observe broadly among loons and grebes,” he adds. In other words, not ducks and geese.
In fact, Chase Brownstein, an evolutionary biologist at Yale University who was not involved in the research, tells the New York Times’ Asher Elbein that though the discovery of the fossil is “exciting,” the study hasn’t convinced him on the waterfowl situation.
Either way, "this fossil underscores that Antarctica has much to tell us about the earliest stages of modern bird evolution," Patrick O'Connor, a paleontologist at Ohio University and another co-author on the study, says in the statement.
Fossil evidence suggests that Antarctica had a temperate climate with lots of vegetation 69 million years ago. This has led scientists to speculate on whether Antarctica may have been one of few safe environments, far from the destructive reaches of the Chicxulub impactor, for birds to develop in.
Per the statement, Matthew Lamanna, a co-author of the study and paleontologist at the Carnegie Museum of Natural History, says that "Antarctica is in many ways the final frontier for humanity's understanding of life during the Age of Dinosaurs.”/https://tf-cmsv2-smithsonianmag-media.s3.amazonaws.com/accounts/headshot/Margherita_Bassi.png)