A newly discovered flying dinosaur with wings like a bat is among the earliest which is believed to have evolved to specialise in life among trees.
The discovery of the fossil in northeastern China has challenged the idea that feathered wings were necessary among dinosaurs capable of gliding flight.
It has provided palaeontologists with direct evidence about how dinosaurs evolved into birds, including the unsuccessful routes that evolution took.
The fossil dates back 163 million years to the Jurassic era and has been featured on the cover of the journal Nature, one of the most famous scientific publications in the world.
The new species has been named Ambopteryx longibrachium and scientists believe it measured 32 centimetres (12in) in length and weighed just over 300g (10oz).
Scientists behind the discovery said its membrane wings were supported by a rod-like bone, making them “bat-like” in their appearance.
Ambopteryx belonged to a family on dinosaurs known as scansoriopterygidae, meaning “climbing wings” which are among the earliest fossils discovered of non-avian dinosaurs that were clearly adapted for living in trees.
Dr Wang Min, the author of the study, and a leading palaeontologist at Chinese Academy of Sciences, said the new finding was different from what he had previously seen.
Dr Min said: “We found a long rod-like bone in its forelimb which is not grown in other dinosaur. So it shows feathered wings is not the only way to fly as we previously supposed.”
Some fossils of juvenile scansoriopterygid species do present with simple feathers on their wings.
However scientists suspect they were actually used to glide, and would not have been capable of truly powered flight the way that birds are.