A Cretaceous dinosaur fossil so well preserved we can determine its skin coloring has led to the most realistic reconstruction yet of one of these extinct beasts. It has also given us insight into the environment in which this particular species lived.
When he was a graduate student, Dr Jakob Vinther, now of the University of Bristol, realized that structures on the skins of exceptionally preserved fossils once carried melanin pigments. Earlier this year this idea was used to reconstruct the colors of a 10-million-year-old snake.
Vinther is even more ambitious, tackling a species that has not only been dead for over 120 million years, but lacks modern relatives filling similar ecological niches. In Current Biology, he has reported on pigment-containing “melanosomes” on the skin of a remarkably preserved Psittacosaurus held in Frankfurt's Sekenberg Museum of Natural History.
The Psittacosaurus skeleton. Vinther et al/Current Biology
The Psittacosaurus's skin contains more melanosomes, which indicates a darker color, on top than below. This is a common pattern in animals today – think orcas or penguins when horizontal – for the camouflage it provides. The combination works because sunlight comes from above, making evenly colored objects brighter on top. By reversing this, animals confuse the eyes of predators or prey.
Not all countershading is the same, however. Where sunlight is mostly direct, the most effective form shifts sharply from dark to light – like those orcas again – but diffused light favors a more gradual transition.
A model of Psittacosaurus in its native habitat. Robert Nicholls