Jian changmaensis Emerges as Early Bird Predator With 4-Foot Wingspan in China

Q: This four-winged raptor is blamed for piles of bird bones. What if the real killer remains undiscovered?

Yes. *Jian changmaensis* is the strongest candidate so far, but the case is not closed. The new fossil gives paleontologists their best match yet for the Changma Basin’s mysterious clusters of crushed bird bones, which resemble owl-like pellets. *Jian* was a medium-sized microraptorine dromaeosaur, likely feathered on both forelimbs and hind limbs, with an estimated wingspan of about four feet. It is also the only known non-avian carnivore body fossil from the Xiagou Formation, where more than 100 bird fossils have been found. That makes it a plausible predator of small early birds such as *Gansus yumenensis*. But the researchers themselves describe *Jian* as a “best guess,” not a definitive identification. The evidence is circumstantial: the dinosaur was found in the right place, at the right time, and fits the ecological role, yet no fossil directly links it to the bone piles through stomach contents, bite marks, or an animal preserved with pellets. That leaves open several possibilities. Another predator from the same ecosystem may simply not have been found yet. The bone accumulations could also reflect more than one predator, or behavior unlike that of modern raptors. Fossil records are patchy, and Changma has yielded only a single non-avian dinosaur specimen so far. So *Jian changmaensis* likely fills the missing predator role, but future discoveries could still revise the story.

3 articles · Updated · ScienceDaily · Jun 24

Researchers identified Jian changmaensis from China's Changma Basin as the likely predator behind pellet-like clusters of crushed prehistoric bird bones found at the site.
A 4-inch upper arm bone suggests the feathered dromaeosaur had a roughly 4-foot wingspan, making it one of the largest known microraptors and the only non-bird carnivorous dinosaur recovered there.
Long feathers on both arms and legs indicate a four-winged glider rather than a powered flier, giving scientists a plausible hunter that lived alongside early birds in the same ecosystem.
More than 100 bird fossils have been recovered at Changma, but just this single non-avian dinosaur specimen, making the find a key clue to how early birds and close dinosaur relatives coexisted.