A fossil bed in northwestern China is littered with the remains of hundreds of prehistoric birds—including some whose broken bones were crushed into pellets, similar to those coughed up by modern owls. For years, scientists guessed that a larger predatory animal must have hunted these ancient birds, but they never found direct fossil evidence of this predator. But in a new paper published in the Annals of Carnegie Museum, researchers announced the discovery of a new species of dinosaur from this fossil bed—a cousin of Velociraptor with long feathers on its front and back limbs. Based on the dinosaur's distinctive arm and shoulder bones, scientists hypothesize that this animal is the missing predator.
"Scientists have found these weird, broken-up clusters of bird bones at this site, and we didn't know what made them. This new microraptor dinosaur, Jian changmaensis, is our best guess," says Jingmai O'Connor, the associate curator of fossil reptiles at the Field Museum in Chicago and senior author of the paper describing the new species. "It's the only dinosaur found at this site that wasn't a bird, it was a carnivore, and it was much bigger than everything else that we've found there."
Modern birds are the only group of dinosaurs that survived the after-effects of a meteorite hitting the Earth 66 million years ago. But birds and their fellow dinosaurs lived together for tens of millions of years in the Jurassic and Cretaceous periods. One group of dinosaurs, the dromaeosaurs, were close cousins of the bird-dinosaurs. Dromaeosaurs, like birds, were covered in feathers and tended to be relatively small and speedy. The Velociraptors made famous in Jurassic Park are probably the most famous dromaeosaurs (but they would have been smaller and more feathery than they're depicted in the movies).
The new species, Jian changmaensis, belongs to a clade within the dromaeosaur family called microraptors. Microraptors tended to be small; the most well-known species is about the size of a crow. "Jian is one of the biggest microraptor specimens that has ever been found," says O'Connor. "The piece of its upper arm bone that we have is about 4 inches long, so the entire dinosaur probably had something like a four-foot wingspan, around the size of a barn owl."
And while scientists only have Jian's arm, they suspect that Jian, like its fellow microraptors, had long feathers on both its arms and its legs, giving it the appearance of having four "wings" that it used to glide. "Jian and the other microraptors probably weren't capable of true, powered flight, but they could probably glide like a flying squirrel," says O'Connor.
The new dinosaur's name, Jian changmaensis, is a reference to its bird-like appearance and its place of origin. Jian is a winged creature in Chinese mythology, and the fossil was found in the Changma Basin in China's Gansu province.
"Jian changmaensis reveals that non-avian dinosaurs lived in what is now the Changma Basin, an area famous for its fossil birds," says Matt Lamanna, corresponding author of the study and Carnegie Museum of Natural History's Mary R. Dawson Curator of Vertebrate Paleontology and senior dinosaur researcher. "Our team has recovered more than a hundred bird fossils at Changma, but only this single non-avian dinosaur specimen. Jian provides critical new insight into the biological history of the Changma region and the ecological context of the ancestors of today's birds."
"You cannot understand life on the planet today without looking at its origins," says O'Connor. "Birds are arguably the most successful group of land-dwelling vertebrate animals on Earth today. Learning about early birds and their close non-bird dinosaur relatives gives us a better understanding of what made the group of birds that survived so special."
This study was contributed to by Ling-Qi Zhou (Gansu Geological Museum), Matthew Lamanna (Carnegie Museum of Natural History), Ashley Poust (University of Nebraska State Museum and University of California Museum of Paleontology), Da-Qing Li (Gansu Agricultural University), Hai-Lu You (Institute of Vertebrate Paleontology and Paleoanthropology, Chinese Academy of Sciences), and Jingmai O'Connor (Field Museum).
