In 2003, Beebe's Tetrapteryx hypothesis was supported by the discovery of "Microraptor gui", a small feathered dinosaur which possessed asymmetrical flight feathers on both its front and hind limbs. Beebe's Tetrapteryx hypothesis is now regarded as prescient for its prediction of both the anatomy and likely gliding posture of "Microraptor gui", which Richard O. Prum has described as " as if it could have glided straight out of the pages of Beebe’s notebooks." This animal's discovery has had the effect of resurrecting Beebe's theory that leg feathers played an important role in the origin of bird flight.