Scientists construct a colorful 3D model of the “parrot lizard” to learn about its environment.
When attempting to camouflage themselves, land animals must consider not only the colors of their surrounding, but also the light. Sunlight falling from above illuminates an animal’s back, while the body casts a shadow causing the belly to appear dark — together, these light patterns make the animal stand out rather than blend in.
To counteract these lighting effects, animals are often colored darker on their backsides and lighter on their undersides, in a pattern known as countershading. This pattern gives land animals, like deer, a flat appearance, making them harder to see.
New research published in Current Biology suggests at least one dinosaur veiled itself using countershading too.
Researchers examined a specimen of the 120 million-year-old plant-eating dinosaur Psittacosaurus, or “parrot lizard,” from what is now northeastern China, and found well-preserved fossil melanosomes — tiny structures that carry the light-absorbing pigment melanin.
Melanosome concentrations were highest on the Psittacosaurus’s back and palest on its belly, consistent with countershading.
The researchers were curious whether the distinct color patterns could tell them something about the environment in which the dinosaur lived. To investigate, they constructed a 3D model based on bone measurements, knowledge of muscle structure, and detailed study of preserved scales and pigment patterns.
"Our Psittacosaurus was reconstructed from the inside-out. There are thousands of scales, all different shapes and sizes, and many of them are only partially pigmented,” said study co-author Robert Nicholls in a press release. “It was a painstaking process but we now have the best suggestion as to what this dinosaur really looked like."
To get an idea of how light and shadows played off of this dinosaur, the researchers took their completed model to the Cretaceous plant section of Bristol Botanic Garden and snapped photos out in the open and underneath trees.
The images revealed that the dinosaur’s camouflage was optimal when the light was diffused by trees, meaning Psittacosaurus most likely lived in a forest, rather than an open habitat.
“This demonstrates that fossil colour patterns can provide not only a better picture of what extinct animals looked like, but they can also give new clues about extinct ecologies and habitats,” study lead author Jakob Vinther remarked.
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