A new dino may be the culprit in an ancient murder mystery

The arm and shoulder bones of a gliding dinosaur might have just revealed the solution to a gruesome whodunit. 

Since 2002, researchers have unearthed more than 100 prehistoric bird remains in the Changma Basin. It’s a fossil bed in northwestern China. The remains here date back to about 120 million years ago. Some include hacked-up pellets containing broken bones. Those pellets resemble ones coughed up by today’s owls.

Paleontologists long assumed a meat-eating dinosaur was to blame. But fossil evidence of the predator has been hard to find — until now.

A new species of dinosaur sporting wing feathers on its arms and legs may be to blame. Researchers used shoulder and upper arm bones found in the same fossil bed to identify the new species. Named Jian changmaensis, it belonged to a group of dinosaurs known as microraptors. These small, speedy dinos were cousins of the famed velociraptor. 

The team shared its findings June 4 in the Annals of Carnegie Museum.

Built for gliding

Like other more well-known microraptors, the newfound dino likely used its “wings” to take to the air. This would have helped it glide like a flying squirrel, the researchers say.

Microraptors weren’t birds — though they were close relatives. And several birdlike features may have allowed J. changmaensis to glide better than other microraptors, says Jingmai O’Connor. At the Field Museum in Chicago, Ill., this vertebrate paleontologist studies how birds evolved.

O’Connor’s team spotted one notable feature on the new dino’s upper arm bone, or humerus. Rounded protrusions on the bone, called condyles, help form the elbow. These formed differently in J. changmaensis than in other microraptors.

A structure in the shoulder called the coracoid was also longer in J. changmaensis. “These features are very birdlike,” O’Connor says.

This predator would have dwarfed the early birds it feasted on, the team says. With an estimated 1.22-meter (4-foot) wingspan, the new dino is among the largest microraptors found so far. Its wingspan is about as large as a barn owl’s. 

Understanding ancient ecosystems

The find doesn’t just solve who snacked on the early birds of Changma Basin. It marks the first nonbird dinosaur remains found in the region. 

“It’s a new record from that particular ancient ecosystem, which is exciting,” says Michael Pittman. Before this discovery, all microraptors from the same era had been found at sites in northeastern China. Pittman is a paleontologist at the Chinese University of Hong Kong. He did not take part in the new research, but he does study how animals evolved flight.

Teasing out how well this predator ambushed prey while gliding is a bit tricky, O’Connor says. The birds it feasted on would’ve been more powerful and agile flyers. But the new fossil can help researchers better understand how flight evolved.

Fossils like J. changmaensis show that birds weren’t unique in getting airborne, says Pittman. The find shows what roles microraptors took on in other ecosystems. “It’s such a special ability to be able to fly,” he says. “But there’s still a lot we don’t understand.”