For decades, fossils have been sitting in a museum at the University of California Berkeley – a graduate student named Peter Klose who began stabbing in 2015.
The birds are very large, with wingspan reaching 21 feet (6.4 m). Specific individuals, including fossils, may be the largest of all, the study suggests.
Using the size and dimensions of the fossils, the researchers were able to estimate the size of the rest of the individuals. The bipedal bird is “the largest specimen known to an entire group of endangered pelagornithides”, while the jawbone “is larger, or not larger than the largest known skeletal-toothed bird group.”
“These Antarctic fossils … represent not only the largest flying birds in the Eocene, but also the largest unstable birds ever to live,” the study says.
Klose and other researchers have determined that the bone of the foot is 50 million years old and the jawbone is 40 million years old – evidence of the rise of birds during the Cenozoic period, after an asteroid crashed into Earth and wiped out almost all dinosaurs.
“The extreme and gigantic size of these endangered birds has not exceeded the marine habitat,” added Ashley Post, co-author of the study at the San Diego Museum of Natural History.
Like albatrosses, pelagornithides traveled extensively around the world and could fly over the ocean for weeks. Whales and seals did not dominate the oceans at that time – meaning they were easy prey for giant birds.
“Larger (pelagornithids) albatrosses are twice the size, and these skeletal-toothed birds would have been powerful predators that evolved over the top of their habitat,” said Thomas Steidam, co-author of the study at the Chinese Academy of Sciences. In Beijing.
The study also paints a picture of what Antarctica must have looked like 50 million years ago. It was the habitat of terrestrial mammals, like distant relatives of lazy and anteaters. Antarctic birds, including endangered species of early penguin species and ducks and ostriches, also bred there. Pelagornithids would coexist with others in this habitat.
“I think Antarctica was a rich and diverse place,” said Thomas Morse, senior curator at the Swedish Museum of Natural History. “We only found one percent of those who stayed there.”