Mammals took to the skies around 70 million years earlier than thought, according to scientists analysing the remains of a small squirrel-sized creature that glided in forests in the Mesozoic era in what is now Inner Mongolia.
The specimen found in Daohugou in Inner Mongolia's Ningcheng County has been dated to be at least 125 million years old, which suggests it may have taken flight at the same time as -- and possibly even earlier than -- the first birds.
The creature has been named Volaticotherium antiquus, a composite of Latin and Greek that means "ancient flying beast."
Its fossilised bones suggest a small squirrel-sized mammal quite unlike any other species from the Mesozoic, an era that stretched from 251 to 65 million years ago and encompassed the Triassic, Jurassic and Cretaceous periods.
It had sharp teeth, long, skinny limbs and a fur-covered flap of skin, called a patagium, that probably gave it gliding flight, rather like flying squirrels today -- a species that can glide from tree to tree by stretching out a furry cape.
V. antiquus had small and conical incisors and long, sharp canines.
Put together, this suggests it lived in trees and probably fed on insects at night. It may have been a good glider, but it was unlikely to have had the ability to twist and turn to catch prey in flight, as bats can.
Previously, the earliest known flying mammal was a bat from the Early Eocene era, about 51 million years ago.
The paper appears on Thursday in the British scientific journal Nature. Lead author is Jin Meng of the American Museum of Natural History in New York.