Of course by now, this was simply expected. Yet it is nice to have
outright confirmation.
I also suspect that many land based dinosaurs were feathered in order
to control temperature and to allow activity during the day. Our
perception of the age of dinosaurs has changed to having a large
number of large feathered bird like creatures running around sporting
a pretty colorful plumage.
We have also expanded the type of rocks capable of containing such
fossils.
Canadian
researchers discover fossils of first feathered dinosaurs from North
America
by Staff Writers
Calgary, Canada (SPX) Oct 31, 2012
Researcher
Darla Zelenitsky from the University of Calgary holds a skull of an
ornithomimid preserved with feathers recovered from 75
million-year-old rocks in the badlands of Alberta, Canada. Credit:
Credit: Riley Brandt, University of Calgary.
The ostrich-like
dinosaurs in the original Jurassic Park movie were portrayed as a
herd of scaly, fleet-footed animals being chased by a ferocious
Tyrannosaurus rex. New research published in the prestigious journal
Science reveals this depiction of these bird-mimic dinosaurs is not
entirely accurate - the ornithomimids, as they are scientifically
known, should have had feathers and wings.
The
new study, led bypaleontologists Darla Zelenitsky from the
University of Calgary and Francois Therrien from the Royal Tyrrell
Museum of Palaeontology, describes the first ornithomimid specimens
preserved with feathers, recovered from 75 million-year-old rocks in
the badlands of Alberta, Canada.
"This is a really
exciting discovery as it represents the first feathered dinosaur
specimens found in the Western Hemisphere," says Zelenitsky,
assistant professor at the University of Calgary and lead author of
the study. "Furthermore, despite the many ornithomimid skeletons
known, these specimens are also the first to reveal that
ornithomimids were covered in feathers, like several other groups of
theropod dinosaurs."
The researchers found
evidence of feathers preserved with a juvenile and two adults
skeletons of Ornithomimus, a dinosaur that belongs to the group known
as ornithomimids. This discovery suggests that all ornithomimid
dinosaurs would have had feathers.
The specimens reveal
an interesting pattern of change in feathery plumage during the life
of Ornithomimus. "This dinosaur was covered in down-like
feathers throughout life, but only older individuals developed larger
feathers on the arms, forming wing-like structures," says
Zelenitsky. "This pattern differs from that seen in birds, where
the wings generally develop very young, soon after hatching."
This discovery of
early wings in dinosaurs too big to fly indicates the initial use of
these structures was not for flight. "The fact that wing-like
forelimbs developed in more mature individuals suggests they were
used only later in life, perhaps associated with reproductive
behaviors like display or egg brooding," says Therrien, curator
at the Royal Tyrrell Museum and co-author of the study.
Until now feathered
dinosaur skeletons had been recovered almost exclusively from
fine-grained rocks in China and Germany. "It was previously
thought that feathered dinosaurs could only fossilize in muddy
sediment deposited in quiet waters, such as the bottom of lakes and
lagoons," says Therrien.
"But the
discovery of these ornithomimids in sandstone shows that feathered
dinosaurs can also be preserved in rocks deposited by ancient flowing
rivers."
Because sandstone is
the type of rock that most commonly preserves dinosaur skeletons, the
Canadian discoveries reveal great new potential for the recovery of
feathered dinosaurs worldwide.
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