Dino camouflage hints at forest home
Recent research has found dinosaurs may have cooed instead of roared, and the infamous Tyrannosaurus Rex may have been even bigger than we imagine. Now, using a particularly well-preserved fossil with hints of skin pigmentation intact, researchers at the University of Bristol have managed to produce what they call "the most scientifically accurate life-size model of a dinosaur," and used it to infer the creature's likely habitat.
An ancestor of Triceratops, the Psittacosaurus was a herbivore about the size of a labrador, which lived in Asia about 120 million years ago. The Senckenberg Museum in Frankfurt, Germany, is home to one of the best preserved Psittacosaurus fossils in the world, which still contains segments of skin, complete with what University of Bristol's Jakob Vinther realized were structures that would have carried melanin pigments. He was then able to map out the creature's skin pattern and found that it reflected a type of camouflage commonly used by animals today.
"The fossil … preserves clear countershading, which has been shown to function by counter-illuminating shadows on a body, thus making an animal appear optically flat to the eye of the beholder," says Vinther.
Out in the wild, animals and objects will usually be lit from above by the sun, resulting in them appearing lighter on top and darker underneath, which makes them appear solid and easy to spot. But animals with a countershading pattern invert this to avoid predators, being generally darker on their upper body with a lighter colored belly, which better hides them from view.
To test how well a countershaded Psittacosaurus could hide and determine what kind of habitat it may have lived in, the researchers built a physical 3D model of the Psittacosaurus using the Senckenberg specimen as a base. They measured its bones and noted the pigmentation, and collaborated with palaeontologists to determine its muscle structure. Bob Nicholls, an artist who specializes in recreating anatomically-correct drawings and models of extinct animals, came on board to help build the Psittacosaurus as accurately as possible.
"Our Psittacosaurus was reconstructed from the inside-out," says Nicholls. "There are thousands of scales, all different shapes and sizes, and many of them are only partially pigmented. It was a painstaking process but we now have the best suggestion as to what this dinosaur really looked like."
The team then took the completed model out into the field to test its hide 'n' seek skills, along with a second version that was painted a solid gray color, to study how the shadows fell across it. Photographed under trees in the Bristol Botanic Garden, the Psittacosaurus seemed particularly well-suited to a world of diffuse lighting, like that filtering down through a canopy of trees.
"By reconstructing a life-size 3D model, we were able to not only see how the patterns of shading changed over the body, but also that it matched the sort of camouflage which would work best in a forested environment," says Innes Cuthill, co-author of the study.
"This demonstrates that fossil color 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," confirms Vinther. "We were amazed to see how well these color patterns actually worked to camouflage this little dinosaur."
The research was published in the journal Current Biology. The team demonstrate the project in the video below.
Source: University of Bristol