Fossil of 10-Foot ‘Terror Bird’ Is Discovered
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The fossil of a giant carnivorous bird has been found in Patagonia, marking the largest-known avian skull to have been found.
The fearsome fossil of a 10-foot-tall extinct phorusrhacid or “terror bird” is unveiled today in the journal Nature by Luis Chiappe and Sara Bertelli of the Dinosaur Institute at the Natural History Museum of Los Angeles County.
The phorusrhacids were vicious flightless birds able to snap up dog-sized creatures that flourished in South America between 60 million and 2 million years ago. The find suggests that these monstrous birds, which are thought to have weighed up to half a ton, were probably more agile and less portly than previously thought.
The new fossil was discovered in 15 million-year-old rocks in Patagonia, located in Comallo, Argentina. The specimen includes a limb bone and a horse-sized, virtually complete, skull of a gigantic phorusrhacid with an eagle-like bill. Apart from the fossil being evidence of the largest-known bird, the find is significant because it suggests important changes that occurred during the terror bird’s evolution, notably in their agility.
“Our study shows that the skulls of the largest terror birds were very different from those of their smaller relatives,”Mr. Chiappe said. The new study of the 28-inch skull challenges the traditional view that during the birds’ evolution, they became slower and less agile as they grew more corpulent, he said.
During much of the time that terror birds existed, South America was an island continent where species evolved in isolation from the rest of the world.
With no large carnivorous mammals to compete with, the terror birds became the top predators.
“The new fossil adds significantly to our knowledge of the evolution of terror birds,” Mr. Chiappe said. “Future discoveries are likely to reveal a much greater diversity of these fascinating birds.”
Scientists believe that the extinct birds were meat-eaters because their beaks resemble those of predatory eagles and scavenging vultures. Another clue comes from the dining habits of the closest living relatives of terror birds — the Seriemas. The family of South American birds preys on lizards, snakes, and small birds from the air.