A new species of prehistoric, four-winged dinosaur discovered in China may be the largest flying reptile of its kind.

The well-preserved, complete skeleton of the dinosaur Changyuraptor yangi features a long tail with feathers 30cm in length – the longest ever seen on a dinosaur fossil. The feathers may have played a major role in flight control, say scientists in the latest issue of Nature Communications, in particular allowing the animal to reduce its speed to land safely.

The 125m-year-old fossil, believed to be an adult, is completely covered in feathers, including long feathers attached to its legs that give the appearance of a second set of wings or "hind wings". It is the largest four-winged dinosaur ever found, 60% larger than the previous record holder, Microraptor zhaoianus, in the family of dinosaurs known as microraptors.

These beasts were smaller versions of their closely related, larger cousins, the velociraptors made famous in the Jurassic Park movies. They belong to an even wider group including the king of all dinosaurs, Tyrannosaurus rex. At 1.3 metres long and weighing 4kg, the meat-eating C. yangi is one of the largest members of the microraptor family, which tended to weigh 1kg or less.

Microraptors, which are close relatives of modern birds, had many anatomical features that are now only seen in birds, such as hollow bones, nesting behavior, feathers and possibly flight. They were dinosaurs rather than pterosaurs, the more well known flying prehistoric reptiles.

"C. yangi was [like] a big turkey with a really long tail," said Dr Alan Turner from Stony Brook University, one of the authors of the paper. "We don't know for sure if C. yangi was flying or gliding, but we can sort of piece together this bigger model by looking at what its tail could do. Whether or not this animal could fly is part of a bigger puzzle and we're adding a piece to that puzzle."

The fossil was discovered in Liaoning province, northeastern China, an area noted for the large number of feathered dinosaurs found over the past decade, including the first widely acknowledged feathered dinosaur, Sinosauropteryx prima, in 1996.

Before this study, it was thought that the small size of microraptors was a key adaptation needed for flight, but the discovery of C. yangi suggests that aerial ability was not restricted to smaller animals in this group.