Bat-Winged Dinosaurs Took 150 Million Years to Evolve Into Expert Fliers

They weren't born with an automatic knack for flight.

The body composition of two, tiny, bat-like dinosaurs made them more likely to be fallers than fliers, to paraphrase Littlefoot. Yi qi and Ambopteryx longibrachium used their wings to glide – just not all that successfully, according to a new study in the journal iScience.

Dr. T. Alexander Dececchi, a paleontologist at Mount Marty University, and the other researchers utilized a technique called laser-stimulated fluorescence on the remains of a Yi to get information about soft tissue and bone configurations. They used the details to reconstruct how the dinosaur’s membrane and its supporting styliform bone may have looked and functioned. For the Ambopteryx, the team applied the results to create a similar model. Then they tried to figure out if these two types of dinosaurs were fliers, gliders, or neither.

Mathematical models let Dececchi and the others plug in different sizes for the dinosaurs’ weight and wingspan, as well as try various wing shapes and muscle configuration. Based on their findings, they conclude that neither species was likely able to take off from the ground. While they have plausible ranges of body and wing size for gliding, they were probably pretty mediocre at it.

Compared to other animals that glide with the greatest of ease, the dinosaurs would need to be faster and leap from higher points to stay in flight. That makes it harder to land safely.

“If you’re going to be flying fast into a tree, it increases the chance you’re going to hurt yourself when you crash,” Dececchi told Popular Science. That inelegance, paired with legs not well-suited for running, could’ve contributed to these dinosaurs’ downfall, as better fliers, like Archaeopteryx, started competing for resources.

If Yi and Ambopteryx hadn’t gone extinct, they may have evolved to become better fliers. Pterosaurs started off clumsy but improved over millions of years. That’s according to a new study, published in Nature, from the University of Reading. Dr. Chris Venditti and the team used fossil remains of pterosaurs and metabolic rates of birds to estimate how far the reptiles could fly or glide before needing to stop.

Pterosaurs aren’t dinosaurs, but they did overlap with some of them. The winged lizards — what many of us grew up calling pterodactyls — are a group of around 200 known species. They started flying millions of years before birds and bats. Their membranous wings are more similar to bats and Yi and Ambopteryx than they are to birds.

Even as animals did gain the ability to fly, not all of them were as successful and there’s not necessarily a straight line you can draw between one extinct species and today’s birds. Professor Hans Larsson of McGill University's Redpath Museum, who worked on the study of Yi and Ambopteryx, told the CBC that paleontologists are confident that birds are modern dinosaurs. “What this new study brings in, though, is that it’s not a clearcut, single trajectory going into birds,” he said.

For more dinosaur news, read about the T. rex fossil that was recently sold for $31.8 million and what scientists opinions are after extracting DNA from insects that were preserved in resin – basically Jurassic Park come to life.


Jenny McGrath is a science writer for IGN. She never tweets, but here she is @JennyMcGeez.

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