The stories of dinosaurs’ lives may be written in fossilized pigments, but scientists are still wrangling over how to read them.
In September, paleontologists deduced a dinosaur’s habitat from remnants of melanosomes, pigment structures in the skin. Psittacosaurus, a speckled dinosaur about the size of a golden retriever, had a camouflaging pattern that may have helped it hide in forests, Jakob Vinther and colleagues say.
The dinosaur “was very much on the bottom of the food chain,” says Vinther, of the University of Bristol in England. “It needed to be inconspicuous.”
Identifying ancient pigments can open up a wide new world of dinosaur biology and answer all sorts of lifestyle questions, says zoologist Hannah Rowland of the University of Cambridge. “You might be able to take a fossil … and infer a dinosaur’s life history just from its pigment patterns,” she says. “That’s the most exciting thing.”
Not so fast, says paleontologist Mary Schweitzer of North Carolina State University in Raleigh. Evidence for ancient pigments can be ambiguous. In some cases, microscopic structures that appear to be melanosomes may actually be microbes, she says. “Both hypotheses remain viable until one is shot down with data.” Until then, she says, inferring dinosaur lifestyles from alleged ancient pigments is impossible.
Vinther’s work, published in the Sept. 26 Current Biology, is the latest in a long-simmering debate in the field of paleo color, the study of fossil pigments and what they can reveal about ancient animals. Disputes over his team’s findings and what’s needed to clearly identify fossilized melanosomes point to current pitfalls of the field.
But the promise is clear: Paleo color could paint a vivid picture of a dinosaur’s life, offering clues about behavior, habitat and evolution.
“This is a crucial new piece in the puzzle of how the past looked,” Vinther says.