Chinese scientists have discovered a new dinosaur species which appears to have been equipped - like Batman - with a cape that may have given it the ability to glide.
Researchers say the finding is extraordinary, representing something new in evolutionary history.
The little tree-climbing dinosaur - about the size of a magpie - was equipped with a soft, smooth membrane draped over its long, strong forearms that may have looked like the wings of a bat when spread.
The 163-million-year-old fossil has been named Ambopteryx longibrachium and was found at Wubaiding village, Liaoning province, northeast China, in 2017, according to a paper published in the journal Nature on Thursday.
Lead author Dr Wang Min, a researcher with the Chinese Academy of Sciences' Institute of Vertebrate Palaeontology and Palaeoanthropology in Beijing, said quite a number of dinosaurs had birdlike feathers and some eventually evolved into birds.
"But bat-like wings? The idea has not been widely accepted," he said.
The possibility was first raised a few years ago when a close relative of the newly discovered dinosaur was found, also in China, with a finger bone which had never before been seen in dinosaurs.
A small number of researchers suspected the bone could have been used to hold membrane, but the mainstream scientific community remained sceptical.
Why on earth, some critics argued, would a dinosaur need membrane when it already had feathers?
Ambopteryx longibrachium, nonetheless, had the same peculiar finger bone, only this time scientists were also able to observe a large membrane and a thick layer of hair over its head, neck and shoulders.
The hair and membrane was not an efficient combination for flight aerodynamics. But "in evolution, nothing is impossible", Wang said.
The tiny T. rex cousin that humans could look down onThe dinosaur lived in thick forest and could have been easy prey to large predators. But its wings might have given it the ability to hop from tree to tree, and they could also have been useful when hunting.
Wang and his colleagues found traces of small bones in the remnant of its stomach. While a tree-climbing dinosaur's main diet should have been fruit, it could sometimes hunt as well, according to the researchers.
An absence of a large chest bone suggested the dinosaur could not fly at will, like a bird or bat. It remains unclear how long the species survived, but it eventually vanished, probably because of competition from better-equipped winged animals with all-feather or all-membrane wings.
- South China Morning Post