'Wonderchicken' fossil from Belgium reveals dawn of modern birds
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[March 19, 2020]
By Will Dunham
WASHINGTON (Reuters) - A fossil unearthed
in Belgium dubbed the "Wonderchicken" is providing a rare glimpse into
the early evolution of modern birds at the twilight of the age of
dinosaurs, right before an asteroid impact altered the course of life on
Researchers on Wednesday described a partridge-sized bird named
Asteriornis maastrichtensis that inhabited a seashore environment 66.7
million years ago during the Cretaceous Period. It represents the
oldest-known anatomically modern bird, sharing skull traits with today's
landfowl like chickens, turkeys, quail and pheasants as well as
waterfowl like ducks, geese and swans.
Birds evolved from small feathered dinosaurs roughly 150 million years
ago. Many birds retained primitive features like teeth until the
asteroid struck some 66 million years ago, triggering a mass extinction
that erased three-quarters of Earth's plant and animal species.
A current estimate for the appearance of the common ancestor of all
11,000 living species of birds is somewhere between 100 million and 70
million years ago, based on DNA mutation rates. Until now the oldest
fossil of an anatomically modern bird was one called Vegavis that lived
66.5 million years ago in Antarctica, though there is a debate about its
placement on the bird family tree.
At first glance, the fossil looked unimpressively like a few broken limb
bones poking out of a small rock.
"When we CT scanned the rocks to get a better look at the limb bones we
were shocked to discover an incredible, nearly complete skull peering
out at us from the computer screen," said University of Cambridge
paleontologist Daniel Field, lead author of the research published in
the journal Nature.
"This skull is one of the best preserved fossil bird skulls of any age,
so the fact that it is from such an important point in Earth history is
amazing," Field added.
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Artist's reconstruction of the world's oldest-known anatomically
modern bird, Asteriornis maastrichtensis, in this handout photo
released to Reuters on March 17, 2020. Phillip Krzeminski/Handout
Field coined the "Wonderchicken" nickname, owing to its chicken-like
beak and its scientific importance. Its scientific name Asteriornis
honors Asteria, an ancient Greek goddess of falling stars, a nod to
the imminent asteroid.
Asteriornis provides clues as to which factors may have helped some
birds survive the asteroid impact while others perished, said
paleontologist and study co-author Daniel Ksepka of the Bruce Museum
in Greenwich, Connecticut.
Its relatively small size - a foot-long (30-cm-long) body - - may
have helped it survive as the global environmental calamity caused
by the asteroid strike made it hard for larger animals to find
enough to eat, Ksepka said.
Its adaptation to a shoreline environment, Ksepka added, meant it
would have been spared from the wildfires believed to have destroyed
most of the world's forests after the asteroid impact may have
incinerated tree-dwelling birds.
(Reporting by Will Dunham; Editing by Sandra Maler)
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