Microraptor
gui:
The Four-Winged Dinosaur by
Dave Board
9/21 With every newly discovered feathered
dinosaur fossil, paleontologists are revealing the apparent dearth
of superlatives in the English language. So maybe it's surprising
that the latest "greatest" is called Microraptor: a name
befitting the size-but not the importance-of this wonderful
animal.
I should start this article by saying
Microraptor is real. A real fossil dinosaur with real fossil flight
feathers-on all four limbs. Dinosaurs with feathers on their
bodies have now been found by the dozens. The first came in the
90's, and their arrival was welcomed as a prediction confirmed.
Scientists had long theorized (since Darwin's time, in fact) that
birds were related to reptiles. More and more, the comparison of
dinosaur and bird skeletons revealed similarities. But theories are
made to be broken, and paleontologists breathed a sigh of relief
only when rare well-preserved dinosaur skeletons with fossil
feathers began to turn up in China's Gobi desert.
So
dinosaurs and birds had more than skeletal similarities in common:
they both had feathers. What makes Microraptor so special, of
course, is that the feathers on it's hind limbs-like those on it's
arms and the arms of other feathered dinosaurs-are true flight
feathers. Asymmetrical feathers provide the kind of aerodynamic form
that airplanes employ to provide lift. In previous feathered
dinosaurs, only downy, symmetrical feathers had been associated with
hind limbs.
This is not to say Microraptor gui
was a super-flyer. In fact, it's hard to imagine the little dinosaur
was capable of flapping all four limbs. Likely, it glided between trees
and tree limbs. Which leads to a significant proposal. While a
popular theory of dinosaur scientists says true flight evolved from
the ground up, maybe arboreal dinosaurs were in fact the pioneers of
life in the skies. Microraptor's leg feathers would have dragged
clumsily along if it spent time on the ground, and the previously
mentioned problem of four flapping wings suggests the innovative
creature spent most of it's time among the branches.
Maybe the argument that feathers evolved
for the good of tree-dwelling dinosaurs has finally triumphed in
Microraptor.
Or maybe not. A recent study of living
birds stokes the fires of debate anew: ornithologists report the
observation that some species of ground birds flail their wings
furiously to assist in running up steep slopes. This flapping
motion, it was discovered, does not provide vertical thrust but
instead acts like a spoiler on a race car to press the birds' bodies
to the surface they are trying to scale. The authors suggest
feathers and wings might have first evolved to help young dinosaurs
in a similar fashion.
Insulation from the cold, assistance in
climbing tree trunks, gliding through the tree tops, and soaring
across the sky: maybe it was for a mix of some or all of these
functions that feathers evolved on bipedal dinosaurs. One thing is
certain: Microraptor is the poster child of ingeniously configured
dinosaurs.
The scientific description of Microraptor was
published in the science journal Nature.
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