How the World’s Largest Flying Dinosaur Avoided Crash Landing

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July 15 2014 11:00 AM

How the World’s Largest Flying Dinosaur Avoided Crash Landing

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Changyuraptor yangi was about 4 feet long from tip to tail.

Illustration by Stephanie Abramowicz, Dinosaur Institute, NHM

In the dinosaur world, raptors have a reputation for being ferocious, fast, and having sharp claws to slash open their prey. A new fossil unearthed in China confirms that some raptors could not only rip your face off—they could also fly. The new species, called Changyuraptor yangi, is the largest known flying dinosaur. It was named for its hallmark feature: long feathers (chang yu), which grew on its tail and legs. Changyuraptors and other dinos from their family of raptors are often called “four-winged” dinosaurs because their long feathers make their legs look like a second pair of wings.

This is one of several recent discoveries that suggest flight did not originate with birds but with their dinosaur ancestors. Paleontologist Luis Chiappe has studied the origin of birds for more than two decades, but he was floored when he first saw the Changyuraptor fossil, the subject of a paper in today’s issue of Nature Communications. “It was stunning to see,” he said. “You have the quintessential feature of a bird—these long feathers that are remarkably similar to modern feathers—attached to the body of a fearsome dinosaur like a raptor—sharp teeth, sharp claws, and a long tail.”

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The specimen Chiappe and colleagues studied was around 4 feet long, and they estimate it weighed around 9 pounds. As the largest flying dino, Changyuraptor had extra challenges in flight. Maintaining careful control during landings would have been especially important for survival, since large animals tend to fly faster, which creates the potential for dangerous crashes. Researchers’ analysis of the fossil found that its foot-long tail feathers were great for catching winds and helped direct its flight, especially during landings. “Just the same way you land in a plane, Changyuraptors needed to slow down and pitch their nose up,” said Chiappe. “Otherwise, they would crash.”

Part of the reason scientists were able to make such detailed observations of this fossil has to do with where it came from. This fossil was found in the Jehol Biota, an incredibly rich source of fossils in the Liaoning Province of northeast China. Hundreds of exceptionally well-preserved fossils have been found in this area, due in part to the conditions of its ancient environment. When Changyuraptor lived—120 million years ago, during the early Cretaceous period—the area was densely forested, with small lakes and streams and many active volcanoes. Volcanic ash buried animal corpses on land and in water; some were even buried in sudden, Pompeii-like eruptions. Lakes in the area had very little oxygen, which meant specimens were not scavenged by other animals, and were less prone to decomposition by bacteria. This preserved delicate soft tissues like feathers, skin, muscle, and guts.

Despite the exceptional preservation of this specimen, it wasn’t perfect; Chiappe said that in the fossil they studied, the Changyuraptor’s legs overlapped. Chiappe and his team believe these “hindwings” were useful in flight, but its not yet clear how useful.

This is a rare glimpse into the beginning stages of flight evolution, showing that even fairly sizeable dinosaurs could fly. “In the context of a dinosaur, this is a small guy, but in the context of a flier, it’s quite sizeable,” said Chiappe. “I’m sure we’ll find even bigger animals in the future.”

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The exquisite 120-million-year-old fossil shows feathers on the wings and legs.

Courtesy of Luis Chiappe

Jane C. Hu has a Ph.D. in psychology from the University of California–Berkeley and is a 2014 AAAS Mass Media Fellow. Follow her on Twitter.

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