A Dinosaur That Flew on Bat-like Wings

In one sense, the dinosaurs never went extinct. While you're not going to run into a Triceratops or a Tyrannosaurus ambling about anywhere, you've probably seen countless dinosaurs in your life — tiny, colourful little dinosaurs chirping to each other as they flit from branch to branch. Around 150 million years ago, a group of dinosaurs began down an evolutionary path that would carry them past the mass extinction and transform them into birds.

Over the last few decades, researchers have found evidence of feathers on fossils of dozens of dinosaur species, making the image of feathered dinosaurs commonplace. The consensus is that feathers were mainly for display during their early evolution, and were only co-opted for flight later. A newly-described fossil suggests that some dinosaurs may have found another route to the air — on bat-like wings.

The fossil was originally found by a farmer, Wang Jianrong, near Mutoudeng, a village in China's Hebei Province. In a Nature paper, researchers describe the fossil as a new species, Yi qi (pronounced "ee chee"), a member of a group of climbing dinosaurs known as scansoriopterygids, which are some of the smallest known dinosaurs. This specimen, which they believe was an adult, probably weighed around 380g — about the same as a football. It had a small, heavily feathered head and a short, blunt snout with a downturned jaw and forward pointing teeth, like other scansoriopterygids and some basal bird species.

What makes Yi qi special is a slightly curved rod-like bone attached at each wrist. The team also found preserved patches of soft tissue around the long rod and the digits of each hand. Together, the bone and soft tissue probably formed an aerodynamic membrane which Yi qi used for gliding or even flying, a structure that has never been seen in other dinosaurs. (Though pterosaurs, including pterodactyls, are ancient, famous, extinct reptiles from around the same time period, they are not dinosaurs.)

Although Yi qi probably took to the air on this "wing", the researchers are still unsure about how it flew. There's no evidence that Yi qi had powerful flight muscles, and the long rod may have been too unwieldy for flapping flight. On the other hand, gliding membranes tend to stretch along an animal's body; Yi qi's membrane was on its forelimb, which would reduce stability and make control more difficult. It's possible that the little critter used a combination of the two, or that undiscovered features made one flight mode preferable. For the moment, we just don't know.

It's wonderful to see this long-lost world grow ever more diverse. I would love to be ten years old again, my head burstingly full of names and pictures of dinosaurs, overflowing with knowledge about their lifestyle. This time, though, it wouldn't be a drab world of lumbering grey and brown giant reptiles, but one also peopled by their colourful feathered cousins, including a tiny dinosaur with feathers on its head swooping among the gingko trees with bat-like wings.

Ref
Xu, X. et al. "A bizarre Jurassic maniraptoran theropod with preserved evidence of membranous wings". Nature advanced online publication. (2015) doi:10.1038/nature1442

Image credits
The rendition of Yi qi is by Emily Willoughby and is distributed under a CC-BY-SA license via Wikimedia Commons.