In "The Age of Dinosaurs," birds and pterosaurs (winged
reptiles) did not rule the sky alone as previously thought. The
Mesozoic airspace was also occupied by a "flying squirrel" that
could glide down from treetops like a bat.
Chinese scientists have uncovered the fossilized remains of a
small, squirrel-sized mammal that lived at least 125 million years
ago during the Mesozoic era (248 million to 65 million years ago),
at a time when dinosaurs were the dominant creatures on earth.
Unlike known Mesozoic mammals, the fossil had a sizable furry
patagium similar to a bird's feathers, providing direct evidence of
gliding flight that is rare in fossil records.
This finding extends the earliest record of mammalian gliding
flight to at least 70 million years ago. The previous one was by a
fossil bat dating back about 51 million years and uncovered in
North America.
"So far it is the only known mammal that could be seen in the
sky during 'The Age of the Dinosaurs'," said Wang Yuanqing, a
researcher at the Chinese Academy of Sciences' Institute of
Vertebrate Paleontology and Paleoanthropology.
"It changes our thinking about life during the Mesozoic
era."
Along with Meng Jin at the American Museum of Natural History's
Paleontology Department, Hu Yaoming, Wang Yuanqing, Wang Xiaolin
and Li Chuankui from the institute published their findings in the
most recent issue of Nature, the prestigious British
science journal.
The incredibly well-preserved fossil, named Volaticotherium
antiquus (meaning "ancient flying beast" in Latin), was found
in the dinosaur fossil beds of Inner Mongolia's Ningcheng County, already
home to many rich discoveries.
According to the article, the discovery demonstrates that early
mammals were diverse in their means of movement and lifestyles.
Mammals had experimented with gliding around the same time, if not
earlier, as when birds were taking to the sky.
With a length of 12-14 centimeters and an estimated weight of
about 70 grams similar to that of the modern flying squirrel, the
creature had a furry patagium supported by four elongated limbs and
a long tail. Its unique limb and teeth structure demonstrate that
it was a tree dweller that could forage on trees similar to some
existent gliding mammals.
"Its structure shows that it could gain altitude by climbing to
a launch pad for a glide," Wang said. Like bats, it was an
insect-eating animal "but it could not catch insects in flight like
bats," Wang added.
(China Daily December 14, 2006)
