A new fossil species of flying reptile with a wingspan of less than 30cm (1ft) has been discovered in China.
The fossil is one of the smallest pterosaurs known to science
The nearly complete articulated skeleton was unearthed in fossil beds from north-eastern China.
The 120-million-year-old reptile had not reached adulthood when it died, but neither was it a hatchling.
Study of the fossil suggests it is one of the smallest pterosaurs known, a team says in the journal Proceedings of the National Academy of Sciences.
The new species has been named Nemicolopterus crypticus, which means "hidden flying forest dweller".
The researchers from Brazil and China say the toothless, sparrow-sized specimen contains several unique anatomical features that distinguish it from other pterosaurs (ancient flying reptiles).
For example, some of the foot bones are curved in a way not seen in other members of this reptile group. This, say the authors, indicates the pint-sized creature spent much of its time living in the trees.
The new species survived on a diet of insects, say the researchers
"It is very likely that this pterosaur represents a lineage of arboreal creatures that lived and foraged for insects in the gymnosperm forest canopy of north-east China during the Early Cretaceous," the researchers write in PNAS.
They add that its life among the gingko forests of China marks this species as a rarity among pterosaur species.
"The fundamental importance of this discovery is that it opens a new chapter in the history of evolution of flying reptiles," said co-author Alexander Kellner of Rio de Janeiro Federal University's National Museum.
"Until now, it was unknown that some of these animals had these adaptations to live on tree canopies."
Matthew Carrano, a palaeontologist at the Smithsonian Institution in Washington DC said some smaller specimens had been found, but those were clearly younger than this animal.
"It is interesting to see some clear arboreal adaptations in this species," said Dr Carrano, who was not on the research team.
"It confirms a suspicion we had, that pterosaurs were more diverse in their habitats than we knew from the [fossil] record."
Pterosaurs lived alongside the dinosaurs, from 228 million years ago to 65 million years ago. They were the first vertebrates to evolve winged flight.
One pterosaur known as Quetzalcoatlus was enormous, sporting a wingspan of up to 11m (36ft), placing it among the largest flying animals ever.