A new feathered dinosaur unearthed from Jurassic rocks in northeastern China had long bones protruding from its wrists that may have supported wing membranes—like the kind you’d find in bats and flying squirrels, not birds. Yi qi, as the critter is called, is an extraordinary example of early evolutionary experiments with flight. Although ultimately, it may have been a failed experiment. The findings were published in Nature this week.
“The picture of the evolution of feathers and flight has become richer and more complicated as other feathered dinosaurs have been discovered, seemingly on a monthly basis,” UC Berkeley’s Kevin Padian writes in an accompanying News & Views article. “But things have just gone from the strange to the bizarre.”
A local farmer discovered the partial skeleton, complete with preserved soft tissue, in 160-million-year-old sediments of the Tiaojishan Formation in Hebei Province. When a team led by Linyi University’s Xing Xu and Xiaoting Zheng analyzed the fossilized remains, they thought at first that the new 380-gram (0.8-lb) , pigeon-sized dinosaur was flightless: While it sported plenty of feathers, they seemed too narrow and filament-like to form useful flight surfaces. But perhaps it had a different type of wing altogether? After all, an unusually long, slightly curved, rod-like bone extends from each of its wrists, and patches of membranous tissue were preserved alongside the long bones.
A flight apparatus like this has never been seen in a dinosaur before, though it has evolved in other groups. Many flying and gliding creatures these days have long rods of either bone or cartilage associated with a pair of limb joints, and they’re used to anchor aerodynamic membranes like skin. And pterosaurs (which aren’t dinosaurs), have a wing membrane supported by a single elongated finger, The Conversation explains.
“We thought giving this animal a name meaning ‘strange wing’ [in Mandarin] was appropriate, because no other bird or dinosaur has a wing of the same kind,” Xu says in an Institute of Vertebrate Paleontology and Paleoanthropology (IVPP) news release. “We don’t know if Yi qi was flapping, or gliding, or both, but it definitely evolved a wing that is unique in the context of the transition from dinosaurs to birds.” Yi qi (pronounced “ee chee”) is also the shortest name given to a dinosaur ever.
Colleagues joked that these rods could have been used as ski poles or chopsticks, and less jokingly, as part of a courtship display. Unfortunately, because of incomplete preservation, the researchers weren’t able to figure out the size and shape of the wing membrane or the configuration of the bones. And even if Yi qi could flap or glide, it may have only been able to do so for short flights between trees or downwards from elevated perches.
“Yi qi lived in the Jurassic, so it was a pioneer in the evolution of flight on the line to birds,” Zheng adds in the IVPP statement. “It reminds us that the early history of flight was full of innovations, not all of which survived.” Yi qi, with its 60-centimeter (24-inch) wingspan, may represent a whacky evolutionary experiment that ultimately failed.
Images: Dinostar Co. Ltd (top), Zang Hailong/IVPP (middle)