Meet Jianianhualong tengi - a new species of chicken-like dinosaur and a close relative of modern birds that has been discovered by an international team of experts, co-led by a University of Hong Kong paleontologist in China.
This species is not only interesting for being a new feathered dinosaur from the region, but also for having asymmetrical feathers, a feature commonly associated with flight.
Long-tailed, one-meter long and weighing about 2.5 kilograms, it lived some 125 million years ago, and was found in northeastern China in Baicai Gou, Liaoning province, the team reported in the journal Nature Communications. It is part of a family of bird-like dinosaurs called troodontids, which together with another dinosaur family, dromaeosaurids, are the closest relatives to birds.
"Troodontids and dromaeosaurids are bird-like dinosaur groups that share their closest common ancestor with birds. This is like chimpanzees and bonobos sharing their closest common ancestor with humans," explained Michael Pittman, of HKU's department of earth sciences.
Large feathers adorned the forelimbs, hind limbs and tail of Jianianhualong tengi. Those on the tail show a frond-like arrangement just like the iconic early long-tailed bird Archaeopteryx, suggesting this was a relatively common feature in early birds and closely related bird-like dinosaurs.
Pittman said the discovery's importance is that Jianianhualong tengi possessed asymmetrical feathers, a feature commonly associated with flight. Its tail feathers are asymmetrically vanned - one side of the feather is wider than the other - just like in living birds and the "four-winged" gliding dromaeosaurid Microraptor that lived about 120 million years ago.
"The asymmetrical feathers that we reported on the tail of Jianianhualong tengi is the first record of these aerodynamically associated feathers in troodontid dinosaurs," Pittman said. "This means that this feature evolved earlier than previously thought - at least 160 million years ago - because a common ancestor is always older than its descendant groups."
Birds have asymmetrical feathers associated with flight capability, but they are also found in species that do not fly.
Professor Xing Xu, from the Institute of Vertebrate Paleontology and Paleoanthropology, of the Beijing- headquartered Chinese Academy of Sciences, and Professor Philip Currie, from the University of Alberta, Canada, co-led the research.