A group of Yale researchers have brought us one step closer to discovering exactly what dinosaurs looked like.
According to new research published last Tuesday by Derek Briggs, director of the Peabody Museum, and his team, some dinosaurs may have had iridescent feathers. The team analyzed a group of fossils that were more than 40 million years old and showed that structures previously thought to be bacteria were in fact color-producing nanostructures called melanosomes. The finding may help shed light precise physical appearance of dinosaurs and other extinct mammals, including their coloration — a difficult task, considering that pigments often do not survive in fossils.
“We never anticipated that we could reconstruct these fossil plumages,” Richard Prum, professor of ornithology and co-author on the study, said. “We’ve added a whole new dimension to the study of paleontology.”
The finding was largely coincidental — and far from a result the researchers could have predicted, he said.
Jakob Vinther GRAD ’11, a fossilized squid ink enthusiast, first conceived of the project as a way to examine the process of pigment fossilization.
The team analyzed preserved bits of feathers from Germany’s Messel Oil Shale deposits, an area known for producing highly-detailed and intact fossils, for pigment structures. Vinther observed “sausage-like” structures on the fossilized feathers that looked to him distinctly like the skin pigment melanin, a substance he had worked with extensively in the past.
“‘Dude, that looks like melanin!’ ” Vinther said he remembers exclaiming, adding that the shapes appeared to be more organized than one could expect from a bacteria.
In the 1980s, analysts had concluded that the tiny structures observed were remnants of ancient bacteria. But Briggs and his team decided to take another look, using scanning electron microscopy to examine the fossils, which helped them confirm their suspicions.
Brigg’s team cannot trace the feather to a particular species, as the feather was separated from its skeleton. However, they are certain the creature was black with a blue, green or coppery sheen.
Dr. Matthew Carrano, curator of dinosaurs at the Smithsonian Institute’s National Museum of Natural History, said paleontologists run into problems when trying to reconstruct the colors of extinct animals, since colors are typically produced by cells that have long since decayed in fossils.
But, Carrano said, the authors took an important piece of information — the structure of the objects — and used it to great advantage.
“They know that some colors, specifically iridescence, are not created by pigments in cells, but rather by the physical structure of the object itself,” he said. “At a micro-structural level, the surface is constructed so that it reflects light of certain wavelengths, which we see as colors.”
H. Richard Lane, program director of Sedimentary Geology and Paleobiology at the National Science Foundation, which helped fund the study along with the National Geographic Society and Yale University, noted the importance of color in understanding how dinosaurs lived. For example, certain colorings can suggest that the organism required camouflage in their environment.
National Geographic magazine editor Chris Sloan agreed about the importance of this study.
“[It] opens up a whole new way of looking at the ancient world and really bringing it to life in color,” he said, adding that, as a result of this work, artists will soon be able to represent the past in a way that is scientifically correct.
Prum said the next step is to look at fossils of dinosaurs that are theropods, which includes birds and feathered dinosaurs.
“The challenge is getting access to the specimens,” Prum said. “If we had full access to the specimens we need, we could know what dinosaurs really look like by Christmas. It’s just a matter of time.”