A beautifully colored dinosaur fossil is the first to show evidence of countershading, a type of camouflage.


Well-preserved fossil remains of a dinosaur show evidence that it
sported darker and lighter colors as camouflage.
PHOTOGRAPH BY JAKOB VINTHER, UNIVERSITY OF BRISTOL
By Traci Watson
PUBLISHED SEPTEMBER 14, 2016
Surrounded by hungry predators, a little plant-eating dinosaur from
the early Cretaceous did the only sensible thing. It donned
camouflage.


Analysis of the exquisitely preserved fossil remains has revealed one
of the most elaborate dinosaur paint jobs ever seen, including a brown
back and a lighter belly. Modern-day antelope, fish and other animals
have similar dark-and-light zones, which confuse predators, but this
is the first discovery of such markings on a dinosaur.

“This one is unique,” says paleontologist Jakob Vinther of Britain’s
University of Bristol, co-author of a study describing the fossil
published in the journal Current Biology. “We can very clearly see
that there are color patterns … stripes, spots.”

The fossil is also memorable for a more embarrassing reason: It
appears to be pooping. Protruding from its bottom is a rounded object
much like a dog dropping. The researchers say the object could be a
bone, but its composition suggests fecal material.

Even so, the animal “probably didn’t die while defecating,” Vinther
says via email. Gases from the animal’s decay may have pushed out the
waste, he says, or perhaps the dinosaur’s guts continued to churn
after death.

Dinosaur Camouflage WATCH: See how the world may have looked to
dinosaurs and how they blended into their surroundings.
The fancy-pants reptile is a type known as a Psittacosaurus, or “parrot-lizard.” It was about the size of a golden retriever, with
stubby spikes on its cheeks and a beaked jaw. Luxuriant quills
sprouted along its tail like bristles from a toothbrush.

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This particular Psittacosaurus was unearthed in China, where it lived
some 120 million years ago. It was not a safe neighborhood. Local
predators included Yutyrannus, a T.-rex-like giant weighing a ton or
more, and a smaller T. rex relative named Dilong.

Psittacosaurus’s dark back and lighter belly, visible on the
specimen’s remaining scales, could have helped it stay out of a hungry carnivore’s claws. Modern-day predators rely on an object’s shading to
assess its shape, Vinther explains, and when prey is darker on top
than on the bottom, a color scheme known as countershading, shadows
are minimized and the animals look flatter.

Illustration of dinosaur
The dinosaur Psittacosaurus is the first dinosaur to show evidence of countershading, a type of camouflage in which animals have
darker-colored backs and lighter bellies.
PHOTOGRAPH BY JAKOB VINTHER, UNIVERSITY OF BRISTOL AND BOB NICHOLLS

To learn more about the dinosaur’s environs, the researchers built a
life-size model of the Psittacosaurus and painted it a dull gray,
providing a neutral background for assessing shadows on the body. At a
nearby botanic garden, the model was photographed on both clear and
cloudy days, out in the open and under cover of vegetation.

The images show that the Psittacosaurus’s coloring provided the best
camouflage in diffuse light, not full sun. So the reptile probably
lived in the forest rather than on the savanna, the researchers
conclude.

The dinosaur’s dark pigments probably served other purposes as well.
Dark stripes on the inside of its legs may have warded off insects,
like the slashes adorning the legs of modern-day zebras. And spots on
the outside of the front legs could have hardened the skin, thanks to
the toughening qualities of pigment molecules.

Other scientists say that given the difficulty of reconstructing
extinct animals and their environments, the new study makes a good
case that this animal turned to camouflage.

“It’s no surprise” that a dinosaur should do so, paleontologist David
Hone of Britain’s Queen Mary University of London says via email. But
“it is very important as it shows that these patterns really were
present. … That gives confidence we will find more, and then can start
to see how things change over time.”


WATCH: See how a team built a life-size sculpture of the dinosaur Psittacosaurus to to see what its camouflage would have looked like in
real life.
The new results are “very cool,” says paleontologist Gareth Dyke of
Hungary’s University of Debrecen, who has found that the extinct
reptiles known as mosasaurs had dark backs and may have had light
bellies. What’s interesting, Dyke says, is “the variety of different
colors seen on this single fossil. We don’t see that, as far as I
know, in many, if any other, fossil dinosaurs.”

Feathered dinosaurs are known to have boasted beautifully colored
plumage, but Vinther argues that this specimen had scales, not
feathers. And that makes this Psittacosaurus the clear winner in its
division of the dinosaur beauty contest.

“This is definitely the best specimen,” says Vinther, “the Holy Grail
for naked dinosaurs.”

http://news.nationalgeographic.com/2016/09/dinosaur-camouflage-fossil-find/

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