Researchers working in China have unearthed the biggest “four-winged” dinosaur, and its 30-centimeter tail feathers are by far the longest feathers of any dinosaur known. They’ve named it Changyuraptor yangi, and the new species could provide answers for how flight took off.
Microraptorines are a group of predatory, feathered non-avian dinosaurs from the Cretaceous. Some of these are called “four-winged” because of their well-developed wings and the long feathers attached to their legs (or hindwings).
“Numerous anatomical features and behaviors that we have long associated with birds in fact evolved in dinosaurs long before the first birds arrived on the scene,” study coauthor Alan Turner from Stony Brook says in a news release. Hollow bones, nesting behavior, feathers, and possibly flight, for example. Looking at feathered dinosaurs close to the origin of birds could help researchers “understand how gliding or flight aerodynamics evolved, and whether these traits were inherited by the earliest birds,” he adds.
These 125-million-year-old fossils were discovered in an Early Cretaceous formation in Liaoning Province of northeastern China. A well-preserved set of feathers covered its entire body, including its bony tail. At nearly 30 centimeters (almost a foot) long, the exceptional tail feathers make up 30 percent the length of the entire skeleton. Additionally, Changyuraptor weighed 4 kilograms (9 pounds) and measured 1.2 meters (4 feet), making it the biggest four-winged dinosaur of all.
An international team of researchers led by Luis Chiappe from the Natural History Museum of Los Angeles County described the new dinosaur in Nature Communications this week. The genus name combines “Changyu,” meaning “long feather” in Chinese and “raptor,” referring to their predatory habits. The species is named after Yang Yandong of Bohai University.
You might remember Microraptor, a small four-winged dinosaur that lived in China about 120 million years ago. According to a study last year, this Changyuraptor-relative didn’t fly like a bird: It glided from trees. Then there’s the famous Archaeopteryx from Jurassic Germany around 150 million years ago. Its tail feathers were up to 11.4 centimeters (4.5 inches) long, but whether this “transitional form” could fly or not is still debated.
Back to Changyuraptor. Its bony tail and feathers aren’t like the short tails in birds today, “so how it functioned aerodynamically would have been quite different,” Turner explains. “However, this is exactly the sort of tail we see in the earliest birds and their immediate precursors.”
So what did these remarkably long tails do? The researchers think they helped maintain flight performance. “Flying dinosaurs were not limited to small guys,” Chiappe tells the Los Angeles Times. But an animal doesn’t want to be dragging a lot of extra baggage around either, he adds: “Flight is a very expensive business.”
The team used aerodynamic models to test its function, and their calculations indicate that the long feathered tail was pivotal in decreasing descent speed and assuring a safe landing -- tricky for something so big.
Images: S. Abramowicz, Dinosaur Institute, NHM (top) & L. Chiappe, Dinosaur Institute, NHM (middle)
