Among newly discovered, 160-million-year-old, fossils in northeastern China is one of Yi qi (“Yi” meaning “wing” and “qi” meaning “strange”), a pigeon-sized dinosaur without feathered wings. Instead, Yi qi has a long bone extending from the wrist, which resembles the structure of bat wings.
The long bone is completely new to dinosaurs, and only by comparing it to bats, flying squirrels and the like could the researchers, published in Nature, even guess as to its function. But even though they believe it has to do with flight, how exactly the styliform worked — and whether the Yi qi flapped or glided in the air — is still a mystery:
The mode of aerial locomotion that might have been used by Yi is difficult to reconstruct on the basis of present evidence. Yi may have been capable of flapping flight or only of gliding, or may have combined the two locomotor styles as in many extant birds and some bats. There are some indications that Yi may have relied more on gliding than on flapping, including the lack of strongly expanded muscle attachment surfaces on the forelimb bones and the possibility that the unwieldy styliform element would have interfered with the rapid oscillations and rotations of the distal part of the forelimb needed for efficient flapping flight, but the mode of aerial locomotion that is most likely for Yi remains uncertain. Regardless, the evident occurrence in this taxon of a membranous wing supported by a styliform element represents an unexpected aerodynamic innovation close to the origin of birds, and highlights the breadth of flight-related morphological experimentation that took place in the early stages of paravian history.
Experimentation that seems, at least for now, to have been tried and found wanting.
So the question remains: Who has the better name? Yi qi (“strange wing”)? Or the Deinocheirus mirificus (“horrible hand”)?
For more information, here’s a video by Nature on just how the wings of Yi qi may have looked and why they didn’t work:
Reconstruction top image from Dinostar Co. Ltd.