Hard-headed: prehistoric Texas reptile
boasted bony domed skull
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[September 23, 2016]
By Will Dunham
WASHINGTON (Reuters) - In a warm, lush
region of West Texas crisscrossed with rivers, a bizarre reptile roamed
the Triassic Period landscape about 228 million years ago, boasting a
bony domed head unlike almost any creature that ever appeared on Earth.
Scientists on Thursday described the reptile, named Triopticus primus,
based on a fossilized partial skull dug up in 1940 near Big Spring,
Texas, that had long languished in a drawer in a University of Texas
Its head resembled a battering ram: dome-shaped and composed of
The only other animals with comparable craniums were dinosaurs called
pachycephalosaurs that appeared about 90 million years ago during the
Cretaceous Period and were only distantly related to Triopticus.
Even the internal structure of Triopticus and pachycephalosaurs skulls
There has been a long debate among paleontologists about how
pachycephalosaurs used their heads, whether for head-butting like
bighorn sheep, self-defense or some other purpose. Scientists are
similarly uncertain about Triopticus.
"It's difficult for us to say what the domed morphology would have been
for or what would have 'encouraged' the evolution of this structure,"
said Virginia Tech paleontologist Michelle Stocker, who led the study
published in the journal Current Biology.
The appearance of similar characteristics in creatures that are not
closely related, like the wings of birds, bats and the extinct flying
reptiles called pterosaurs, is called convergent evolution.
"Triopticus is a really interesting example of evolutionary convergence
that shows that what we thought were unique body shapes in many
dinosaurs actually evolved millions of years before in the Triassic
Period," Stocker said.
The researchers think Triopticus may have been up to 10 feet (3 meters)
long, but do not know whether it walked on two legs or four or whether
it ate plants or meat.
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The holotype skull of Triopticus primus is seen during preparation
under the microscope at the University of Texas, in Austin, Texas,
U.S., in this undated handout photo. Matthew Brown/Handout via
Triopticus lived when the very first dinosaurs were appearing,
relatively small ones overshadowed by a diverse collection of
non-dinosaur reptiles. Living in Texas alongside Triopticus were
large, semi-aquatic croc cousins called phytosaurs, big four-legged
meat-eaters called rauisuchians and four-legged armored plant-eaters
Some of these also resembled dinosaurs that appeared much later.
University of Chicago evolutionary biologist Katharine Criswell
said, "It is amazing to think that many of the iconic dinosaur
features that we know and love, such as long snouts, toothless
beaks, armor plates and thickened dome skulls, were arrived at
completely independently up to 100 million years earlier in these
distant reptilian cousins."
(Reporting by Will Dunham; Editing by Sandra Maler)
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