A mammal that was a cross between a bat and a squirrel had mastered gliding while the ancestors of modern birds were still learning to fly.

Fossilised remains of the animal have been found in Mongolia and date back 125 million years to an era when dinosaurs still ruled the world.

It is 15 million years older than the earliest fossil remains of the “nearly modern bird”, Gansus yumenensis, a direct ancestor of the birds we know today. The previously unknown creature is so unusual that palaeontologists had to create a new order of animals to classify it within the mammalian family tree.

It has been named Volatico therium antiquus, meaning ancient gliding beast, and was so well preserved that impressions of fur and part of a skin membrane survive in the rock in which it was found.

The animal, being light and boasting large skin membranes that stretched between the limbs, was one of the most accomplished gliders known.

It is by far the earliest mammalian flier discovered and predates the earliest known bat, which is 51 million years old, by more than 70 million years. The earliest gliding rodent is 30 million years old.

In a report of the discovery, which is published in the journal Nature, the researchers say: “Volaticotherium antiquus shows that mammals had experimented with aerial life much earlier than previously expected; probably at the same time as, if not earlier than, when birds exploited the sky.”

Palaeontologists described the fossil remains as one of the most important discoveries of mammals in the Mesozoic era — 248 to 65 million years ago — for more than a century.

“The new evidence of gliding flight is giving us a dramatically new picture of many of the animals that lived in the age of dinosaurs,” Jin Meng, who led the study, said.

The fossil was found and analysed by a team from the American Museum of Natural History, New York, and the Chinese Academy of Science in Beijing. They said in a statement: “Volaticotherium antiquus is the first known Mesozoic mammal capable of gliding flight, indicating that early mammals were more diverse in their early evolution than scientists had previously thought.”

The “ancient gliding beast” had a body weighing about 2.5oz (70g), making it similar to both bats and flying squirrels.

Its sharp teeth are reminiscent of bats rather than squirrels and it would have used them to crunch insects, although it was probably not quite adept enough at flying to catch them in mid-air.

The creature would most likely have been nocturnal. It had limbs that were suited to running up trees in Cretaceous forests, from where it would have launched itself into the air to glide to lower branches. Skin stretched between the arms and legs, combined with its low body mass, allowed it to glide, and a long, stiff tail would have helped to control direction.

Analysis has ruled out the possibility of it being the ancestor of flying mammals, including bats, flying squirrels, flying marsupials or flying lemurs. It developed flight independently.

This year a fossil of Gansus yumenensis, the nearly modern bird, was dated to 110 million years ago; however, palaeontologists believe that it may have existed up to 140 million years ago.

Archaeopteryx, a proto-bird, dates back 150 million years and is regarded as the earliest bird, although it was closely related to dinosaurs.

• Bats use high-pitched sonar to talk to each other as well as identify prey and obstacles, according to research. In a paper published today by the Royal Society, scientists say that the sonar systems, more sophisticated than military radar, could be used to warn others of their position as well as to locate their prey.
  
  The bats may also have an inbuilt anti-jamming device to stop them getting confused with each other’s calls.

Flying by numbers

228m years ago
First winged reptiles, the pterosaurs

150m years ago
Archaeopteryx, proto-bird

125m years ago
Ancient gliding beast, first flying mammal

110m years ago
Gansus yumenensis, earliest nearly modern bird

65-53m years ago
Modern birds evolved

51m years ago
Earliest fossil bat

30m years ago
Earliest gliding rodent

Source: Times database

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