Researchers have linked a fossil from Jian changmaensis to more than a hundred prehistoric bird remains in the Changma Basin of northwestern China. The dinosaur was described on June 4 in the Annals of Carnegie Museum, and the find may identify the predator behind a site that has puzzled paleontologists since 2002.
The preserved shoulder and upper arm bones point to a microraptor, a small, speedy dinosaur cousin to velociraptor. Researchers estimated a 1.22 meter wingspan, about the size of an owl, and said the animal likely used its wings to glide like a flying squirrel.
Changma Basin bird remains
Since 2002, researchers have found more than a hundred prehistoric bird remains in the Changma Basin of northwestern China. Some of the bones were broken and embedded in regurgitated pellets, which is why paleontologists had long assumed a carnivorous dinosaur was responsible for the accumulation.
Jian changmaensis gives that assumption a sharper outline. Michael Pittman of the Chinese University of Hong Kong said the find was the first nonavian dinosaur specimen found in the region. “It’s a new record from that particular ancient ecosystem, which is exciting,” Pittman said.
Jingmai O’Connor on birdlike bones
Jingmai O’Connor, a vertebrate paleontologist at the Field Museum in Chicago, pointed to the humerus and coracoid as the key pieces of evidence. The humerus had rounded protrusions called condyles that formed differently than in other microraptors, and the coracoid was proportionally longer than in other microraptors. “These features are very birdlike,” O’Connor said.
That birdlike anatomy sits beside a sharper contrast. The birds eaten by Jian changmaensis would have been more agile flyers that relied on powered flight, while the dinosaur itself was a glider rather than a flier in the bird sense. “It’s such a special ability to be able to fly,” Pittman said. “But there’s still a lot we don’t understand.”
China and flight evolution
The fossil does more than attach a name to a long-running mystery in China. It adds a rare nonavian dinosaur specimen from that ancient ecosystem, which gives researchers another body plan to compare as they study how flight evolved in dinosaurs that were not birds.
What the new specimen does not yet settle is how Jian changmaensis caught prey. The bones and pellets point to a predator-prey relationship in the Changma Basin, but the record stops short of showing whether the dinosaur caught birds in flight or took them some other way.
