A dinosaur called Yi qi appears to have lifted a page from pterosaurs’ flight plan.
Protruding from each of the newly discovered dinosaur’s wrists was a weird rodlike bone that may have attached to a fleshy wing that helped the dinosaur glide or fly, researchers report April 29 in Nature.
“We’ve never seen anything like this in a dinosaur before,” says paleontologist Sarah Werning of Stony Brook University in New York. “It’s almost like this dinosaur was pretending to be a pterosaur.”
Pterosaurs, flying reptiles that lived at the same time as dinosaurs, had fleshy wings supported by a short bone called the pteroid bone and a long finger bone.Y. qi’s rodlike bone is similar to the pterosaur’s pteroid bone but is longer. Unlike pterosaurs’ shorter wing-supporting bone, Y. qi’s bone probably sat on the equivalent of humans’ pinkie side of the wrist rather than the thumb side, says study coauthor Xing Xu, a paleontologist at the Institute of Vertebrate Paleontology and Paleoanthropology in Beijing.
The fossil find includes membranous tissue preserved between Y. qi’s rodlike bone and its fingers. But there is only one specimen of Y. qi and it’s not well preserved. So, Xu says, it’s not clear how the dinosaur’s rodlike bone and fleshy wing would have been configured or how well the dinosaur could have glided or flown.
Still, he says, several lines of evidence strongly support Y. qi’s aerodynamic capability. The lengths of the pigeon-sized dinosaur’s forelimbs and potential wingspan are proportionally longer than those of Archaeopteryx, a slightly larger dinosaur-like bird that could glide (SN Online: 7/3/14). Also, rodlike bones covered in tissue membranes tend to accompany flying or gliding, as in bats and flying squirrels, Xu says.
Yi qi, which means strange wing in Mandarin, lived in China roughly 160 million years ago, 10 million years before Archaeopteryx, the team reports. It belonged to the group of dinosaurs called theropods that slowly transitioned into birds (SN Online: 7/31/14). Y. qi probably flew nothing like a bird, Xu says, but it may represent an early trial in dinosaur flight.