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At the end of the Cretaceous Period 66 million years ago, a city-sized asteroid collided with the Yucatán Peninsula of Mexico. Known as the Chicxulub impactor, it doomed nearly all dinosaurs to extinction—except, scientists now believe, for birds. An exceptional fossil recently discovered in Antarctica may prove to be the oldest known modern bird, providing critical insight into the evolutionary lineages of avian species.
The fossil dates back 69 million years, more than 2 million years before the Chicxulub impactor, and is a nearly complete skull belonging to the Vegavis iaai, an extinct bird that scientists have long speculated to be related to waterfowl such as duck and geese. A study published last month in Nature detailed the skull’s characteristics, many of which were unique when compared to birds previously discovered from the Mesozoic Era. The skull boasts a long, narrow, and toothless beak, as well as a distinct brain shape strikingly similar to 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 Nature study, told Science.
This particular Vegavis skull was originally unearthed in 2011 during an expedition to Vega Island, nestled at the tip of the Antarctic Peninsula. Before then, scientists could only rely upon a Vegavis fossil discovered more than 20 years ago, which was missing a large fraction of its skull and thus rendered it difficult to research. Though this discovery did prompt researchers to draw an evolutionary connection between Vegavis and modern birds, the claim wasn’t convincing enough for everyone within the paleontology community.
“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, said 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?”
Indeed, the new skull’s defining characteristics are consistent with modern waterfowl and suggest that it may be related to the ducks and geese we see waddling about today. The fossil, however, also reveals qualities inconsistent with waterfowl, aligning more closely with grebes and loons. These include traces of powerful jaw muscles which are essential for overcoming water resistance when diving, while other parts of the skeleton indicate that Vegavis used its feet for underwater propulsion.
Despite this, the skull nevertheless “underscores that Antarctica has much to tell us about the earliest stages of modern bird evolution,” per Patrick O’Connor, a paleontologist at Ohio University and another co-author on the Nature study.
O’Connor added, in an interview with CNN, that “Antarctica at 69 million years ago didn’t look like it did today. It was actually forested. It was a cool, temperate climate based on most of our modeling.”
Antarctica, then, may have functioned as a safe haven for avian dinosaurs in the wake of the devastating asteroid impact, allowing them to not only to survive, but to thrive.
“Antarctica is in many ways the final frontier for humanity’s understanding of life during the Age of Dinosaurs,” Matthew Lamanna, principal dinosaur researcher at Carnegie Museum of Natural History and another co-author, said.
The full study about the Vegavis skull can be read in Nature.
An exceptionally intact 69 million-year-old fossil belonging to the Vegavis iaai may prove to be the oldest known modern bird.
The Vegavis fossil bears several characteristics similar to modern waterfowl such as ducks and geese.
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Sources: Cretaceous Antarctic bird skull elucidates early avian ecological diversity; Paleontologists Discover Fossil of the Oldest Known Modern Bird—but It Raises More Questions Than It Answers; An ancestor of ducks and geese paddled and dove alongside dinosaurs in Antarctica; Fossil of oldest known modern bird discovered in Antarctica; Cretaceous fossil from Antarctica reveals earliest modern bird
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