Four-winged dinosaur: Scientists just found a four-winged dinosaur in northwestern China, and it may be the predator that left behind piles of crushed bird bones

Paleontologists working in northwestern China had been stuck for years on a strange puzzle. According to a new study, ‘First Non-Avian Theropod (Dromaeosauridae, Microraptorinae) from the Bird-Bearing Lower Cretaceous Xiagou Formation of the Changma Basin, Gansu Province, Northwestern China,’ published in the Annals of Carnegie Museum by Zhou et al. , a fossil site in the Changma Basin has produced the remains of more than 100 prehistoric birds.

But among those remains were clusters of broken bones crushed into pellets, similar to those coughed up by modern owls. The scene was eerily familiar: modern owls, after a meal, make nearly identical pellets, regurgitating the bones of their prey in compressed bundles. Something at Changma had been doing the same thing 124 to 120 million years ago. The trouble was, nobody could find the predator.

Well, now scientists may have cracked it. According to the study in the Annals of Carnegie Museum, researchers have formally described a new species of dinosaur called Jian changmaensis: a feathered, four-limbed glider and close cousin of Velociraptor. The find was led by paleontologists from Chicago’s Field Museum and Pittsburgh’s Carnegie Museum of Natural History. It was the first non-avian dinosaur found at the Changma Basin site. It may also be the predator behind those mysterious bone clusters.


A Velociraptor cousin built to glide
According to the Annals of Carnegie Museum study, Jian changmaensis was a member of a group of dinosaurs called microraptors: small, feathered dromaeosaurs that are among the closest known relatives of modern birds. The same study also found that most microraptors were small, about the size of a crow. Jian was much bigger.

According to Jingmai O'Connor, associate curator of fossil reptiles at the Field Museum and senior author of the Annals of Carnegie Museum study, Jian is one of the largest microraptor specimens ever found. The preserved upper arm bone is about four inches long, indicating that the animal had a wingspan of about four feet, similar to the size of a barn owl.

According to the study, Jian probably had long feathers on both its fore- and hindlimbs, giving it the appearance of having four wings rather than two. O'Connor described Jian and its relatives as probably not capable of true powered flight, but able to glide from tree to tree much like a flying squirrel.

That picture is supported by independent research. According to the study, ‘Microraptor reveals specialized gliding capabilities in multiwinged early paravians,’ published in PNAS, which modeled the gliding flight of Microraptor, the best-known four-winged dinosaur and close relative of Jian, and found that the forewing and hindwing working together produced substantial aerodynamic advantages, suggesting these four-winged dinosaurs were more effective gliders than previously understood.

In a previous PNAS study, ‘Biplane wing planform and flight performance of the feathered dinosaur Microraptor gui,’ Chatterjee and Templin reported asymmetric flight feathers on the arms and legs of Microraptor gui and speculated that its wings may have operated in a staggered biplane-like configuration during gliding flight.

The name and the fossil
The dinosaur’s name derives from both mythology and geography, according to the Annals of Carnegie Museum study. Jian, named for a one-winged bird in Chinese mythology, and changmaensis, referring to the Changma Basin in Gansu Province where the fossil was discovered, according to CNN.

The specimen is incredibly well preserved in three dimensions, a rarity among microraptors, whose fossils are usually crushed flat. Researchers recovered an articulated shoulder girdle and partial forelimb, including specific features of the humerus and a shoulder bone called the coracoid, that set Jian apart from all previously known microraptor species. According to the Carnegie Museum of Natural History, this is also the first definitive microraptor specimen found outside northeastern China, and it may be the youngest microraptor fossil discovered, potentially suggesting that the group lasted longer than scientists thought.

A 120-million-year-old cold case
According to the Field Museum, Jian is the only non-bird dinosaur recovered at the Changma site. It was a carnivore, considerably larger than any of the bird species found there. That combination makes it the most likely culprit behind the clusters of crushed bones, but the researchers aren't ready to call it a definitive match.

According to the study published in the Annals of Carnegie Museum, the corresponding author, Matt Lamanna, Mary R. Dawson Curator of Vertebrate Paleontology at Carnegie Museum of Natural History, said that Jian changmaensis tells us that non-avian dinosaurs lived in what is now the Changma Basin, a region well known for its bird fossils. They have found more than a hundred bird fossils at Changma, but this is the only non-avian dinosaur specimen their team has recovered. Jian provides important new insights into the biological history of the Changma region and the ecological context of the ancestors of today’s birds.

Why it matters today
Today's birds are the only dinosaurs to have survived the asteroid impact that struck Earth 66 million years ago. Understanding what made birds different from their close relatives, such as Jian, helps scientists piece together why birds survived while so many others did not.

The study in the Annals of Carnegie Museum says Jian is important for expanding scientists’ understanding of where and for how long microraptors existed, pushing their range beyond northeastern China and potentially extending their timeline beyond what was previously known. In that light, Jian changmaensis isn't just a 120-million-year-old predator. It's a window into the world that gave rise to every bird alive today.