A remarkable fossil site in northwestern China has yielded hundreds of prehistoric bird remains, including clusters of broken bones compressed into pellet-like masses similar to the bones produced by modern owls. For years, paleontologists suspected that a large predator was responsible for hunting these birds, but no direct evidence of such an animal was ever found.
Now, a newly described dinosaur may provide the answer.
In a study published in History of the Carnegie MuseumResearchers report the discovery of a previously unknown dinosaur species from the same fossil bed. had a feathered relative of the animal Velociraptor It has long feathers on both its forelimbs and hind limbs. Based on the distinctive characteristics of its arm and shoulder bones, scientists believe this dinosaur may have been the predator responsible for the accumulation of the mysterious bird bones.
“Scientists found these strange, broken clusters of bird bones at this site, and we don’t know what made them. This new Microraptor dinosaur, Jian changmensis, is our best guess,” says Jingmei O’Connor, 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 location that wasn’t a bird, it was carnivorous, and it was much larger than anything else we found there.”
a feathered relative of Velociraptor
Today’s birds are the only living dinosaurs to have endured the consequences of the asteroid impact that hit Earth 66 million years ago. But long before that event, birds lived alongside many other dinosaur groups during the Jurassic and Cretaceous periods.
Their closest relatives were the dromaeosaurs, a group of feathered dinosaurs known for being relatively small, agile predators. Velociraptormade famous by Jurassic Park movies, is one of the most famous members of this group (but they would have been smaller and more winged than shown in the movies).
Newly identified species, jian changmensisMicroraptor belongs to a suborder of dromaeosaurs. Most Microraptors were quite small, with some species only reaching the size of a crow.
“Xian is one of the largest Microraptor specimens ever found,” says O’Connor. “The fragment of its upper arm bone we have is about 4 inches long, so the entire dinosaur’s wingspan was probably four feet, about the size of a barn owl.”
four winged gliding dinosaur
Although scientists have recovered only part of the animal’s arm, they suspect jian Shared a key feature with other Microraptors. Long feathers probably covered both his arms and legs, giving the impression of four wings.
Instead of flying like modern birds, these dinosaurs were probably adapted for gliding.
“Giant and other Microraptors were probably not capable of true, powered flight, but they probably could have flown like flying squirrels,” says O’Connor.
The name of the dinosaur reflects both its appearance and the place of its discovery. In Chinese mythology, jian is a winged creature. changmensis Refers to the Changma Basin in Gansu Province, China, where the fossil was discovered.
New insights into early bird ecosystems
According to the researchers, the discovery fills an important gap in the ancient ecosystem represented by the Changma fossil site.
The study’s authors, Mary R. “Xian changmensis shows that non-avian dinosaurs lived in what is now the Changma Basin, an area famous for its fossil birds,” says Matt Lamanna, Dawson curator and senior dinosaur researcher. “Our team has recovered over a hundred bird fossils at Changma, but only one non-avian dinosaur specimen. Jian provides important new insights into the biological history of the Changma region and the ecological context of the ancestors of today’s birds.”
The discovery also helps scientists better understand how birds evolved and how their lineage diverged from their close dinosaur relatives.
“You can’t understand the origins of life on the planet today without looking at it,” says O’Connor. “Birds are arguably the most successful group of land-dwelling vertebrates 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 survive so special.”
The study was contributed by Ling-Qi Zhou (Gansu Geological Museum), Matthew Lamanna (Carnegie Museum of Natural History), Ashley Post (Nebraska State Museum and University of California Museum of Paleontology), Da-Qing Li (Gansu Agricultural University), Hai-Lu Yu (Institute of Vertebrate Paleontology and Paleoanthropology, Chinese Academy of Sciences), and Jingmai O’Connor. (Field Museum).