In a study published in the journal Scientific Reports, the researchers describe Zhenyuanlong suni, a cousin of the famed Velociraptor that lived around 125 million years ago.
The new species is part of the group - known informally as raptors - that would precede birds, the only dinosaurs remaining on Earth today.
But bigger species in the group tend to have shorter forelimbs not well-suited for flight, and paleontologists had never found feathers on one of those big-boned raptors - until now.
Its arm structure couldn't have supported its five-foot-long body with the kind of muscle-powered flight that birds use today. But that doesn't make the fossilized remnants of intricate feathers less exciting: It indicates that other members of the raptor family could have had feathers, too - even the ones not suited for flight.
"This new dinosaur is one of the closest cousins of Velociraptor, but it looks just like a bird," study co-author Steve Brusatte of the University of Edinburgh's School of GeoSciences said in a statement.
"It's a dinosaur with huge wings made up of quill pen feathers, just like an eagle or a vulture. The movies have it wrong - this is what Velociraptor would have looked like too."
He dubbed it a "fluffy feathered poodle from hell".
The debate over how many dinosaurs were feathered is still ongoing. We know that birds must have had a common dinosaur ancestor with feathers, and scientists have found some fossils that take us pretty close to where feathers might have first evolved - but they still aren't sure exactly when feathers first emerged in dinosaurs, or for what purpose.
Zhenyuanlong suni didn't have wings well suited for flight - but it did have the feathers one would need to get off the ground. Because of this, they suspect that suni came after a flying ancestor, losing the capability for muscle-powered flight but retaining the related plumage, perhaps to use its wings for mating displays.
