The beast with the behemoth arms: A dinosaur mystery is solved

WASHINGTON (Reuters) - In July 1965, two
gigantic fossilized dinosaur arms replete with
menacing claws were unearthed in the remote
southern Gobi desert of Mongolia. Measuring 8
feet (2.4 meters), they were the longest arms of
any known bipedal creature in Earth's history.
But nearly everything else was missing, leaving
experts baffled about the nature of this beast
with the behemoth arms. Half a century later,
the mystery has been solved.
Scientists said on Wednesday two almost
complete skeletons of the bizarre 70-million-
year-old creature, Deinocheirus mirificus
(meaning "unusual horrible hand"), show it
boasted a combination of unorthodox traits,
including the famous arms, never before seen in
a single dinosaur.
At 36-feet-long (11 meters) and 6.4 tons, it was
the largest known member of a group of bird-
like dinosaurs called ornithomimosaurs
("ostrich mimics"), the researchers said.
Its back was topped with long spines that
supported a sail-like structure whose function
remains enigmatic. It had fused tail vertebrae
to support tail feathers.
Thriving in an river region, it was an omnivore,
eating fish and plants with a beaked, toothless
snout that flared out to the sides like the
herbivorous duckbilled dinosaurs. It had broad
feet with toes ending in squared-off hooves that
may have helped it stand on wet ground.
Deinocheirus had wide hips and moved slowly
but was capable of defending itself thanks to its
sheer size and its three ripping claws on each
hand. It was virtually as big as the apex
predator in the neighborhood, Tyrannosaurus
rex's cousin Tarbosaurus.
Scientists had speculated for decades about
Deinocheirus. It was accurately recognized as a
type of theropod, the dinosaur branch that
includes giants like T. rex but also the lineage
that evolved into birds - but what type?
"Deinocheirus has remained one the most
mysterious dinosaurs in the world. We found
almost (complete) skeletons of Deinocheirus
and know now how it looked, how big it was
and what it ate," said paleontologist Yuong-Nam
Lee, director of Geological Museum at the Korea
Institute of Geoscience and Mineral Resources
in Daejeon, South Korea.
University of Maryland paleontologist Thomas
Holtz, who wrote a commentary accompanying
the study in the journal Nature, said no one
could have predicted its astonishing array of
attributes.
"I've literally waited my whole life to see
Deinocheirus finally unveiled," Holtz said.
Some bad luck almost prevented the unveiling.
The two new skeletons were found in 2006 and
2009 at Gobi sites in Mongolia. Both
suspiciously were missing their heads and other
key parts. The scientists realized those had
been poached by illegal fossil collectors, with
parts sold off to private collectors.
The missing parts from the 2009 excavation
ended up with a collector in Germany but
fortuitously were seen by Belgian paleontologist
Pascal Godefroit, who recognized what they
were and informed Lee and other scientists.
Lee said the researchers persuaded the
collector to donate the fossils because of their
importance to science. The fossils were
returned to Mongolia in May. But Lee said the
2006 fossils remain missing.