Knowing a dinosaur's true colors doesn’t take fun away for paleoartists

Recreation of Rynchops and Thalassodromeus by paleontologist Mark Witton. Image courtesy of the artist.

Dinosaur coloring becoming more scientific, less guesswork.

Until very recently, artists graced with both skills as illustrators and scientific knowledge about fossils had almost complete freedom to paint dinosaurs the way they wanted. And who could say with certainly that the paleoartist was accurate or completely off base?

A succession of recently published papers will have a significant impact on the way paleoartists approach their work. Two recent studies in Nature and Science build upon the discovery by Jakob Vinther, a Yale graduate student who found that a squid fossil contained melanosomes - pigment-bearing organelles just nanometers in size - known for creating colors in other animals. His study was published in the Royal Society’s Biology Letters in 2008.

Chinese and British researchers reported on their work analyzing melanosomes to recreate the tail feather colors of Sinosauropteryx, a carnivorous dinosaur, in Nature in January of this year.

A week later Science published research co-authored by Vinther and funded by National Geographic that determined all the feather colors of Anchiornis huxleyi, a turkey-sized dinosaur, by analyzing the shape and density of its melanosomes.

These advances are the start of some big changes in dinosaur recreations, according to Mark Witton, PhD, a paleontologist and paleoartist with the University of Portsmouth (UK) School of Earth and Environmental Sciences.

Exciting time for paleontologists. “We’ve all grown up being told that we would never know the color of most fossil animals.” -- Mark Witton, paleoartist

“The new discoveries of the integumentary colors of Sinosauropteryx and Anchiornis change all this in a big way,” says Witton. “The books saying the color of fossil animals is a great unknown will have to be rewritten.”

Witton said prior to today, “paleoartists had little more than educated guesswork to go on with their drawings. As virtually every single book on fossil animals will tell you, color only fossilizes in very rare and specific conditions.” The fossils of some animals, including non-birdy dinosaurs that have been extinct for 65 million years or more, are far too old to reveal details of specific colors, says Witton.

“The best data available may reveal, via preservation of microbes on things like feathers or fur, that an animal had stripes or spots, but not what color they actually were. As such, paleoartists have had to narrow down a likely color palette for their critters using several lines of reasoning.”

According to Witton, they’d consider:

• Could the animals in question see in color? If so, they may sport elaborate colors like blues and reds, whereas animals without color sight are typically duller.
  
  
• What modern animals are the subject species related to? Reptiles (including birds) and fish, for instance, can be much brighter than things like mammals, so we may expect prehistoric representatives of these groups to be similarly dressed. Different integumentary structures like mammalian hair, feathers and scales are also capable of producing different colors, so what sort of integument was the fossil animal likely to be covered in?
  
  
• What did the subject animal do for a living? A large ambush predator, for instance, is more likely to be colored in camouflage tones and patterns than swathes of lurid, bright color. Modern ecological analogues are often used here for guidance.
  
  
• Does the animal bear any obvious ornamental devices like crests, fins or other eye-catching structures? If so, they may be brightly colored or patterned to make them even more eye-popping.

•  How big was the animal? By and large, bigger critters are drabber than smaller ones, so more muted tones are well suited to grander beasts while vibrant, vital colors are more at home on their smaller cousins.

Of course, there are always exceptions to the general rules.

“While there are methods for choosing a color scheme for an animal, 99.9 percent of animal schemes you'll see on restored fossil animals are shots in the dark and, in all likelihood, nothing like the real thing,” says Witton.

Witton said its almost certain that we’ll never know the true colors of every fossil animal but there are plenty of specimens with soft-tissue preservation that may, under closer scrutiny like those reported in the recently published work, suggest color schemes for many fossil animals.

These are exciting times for paleontologists, says Witton. “We’ve all grown up being told that we would never know the color of most fossil animals.”

It’s a safe bet that paleontologists around the world are looking into their specimen drawers with a fresh set of eyes.

Li, Q., Gao, K., Vinther, J., Shawkey, M., Clarke, J., D'Alba, L., Meng, Q., Briggs, D., Miao, L., & Prum, R. (2010). Plumage Color Patterns of an Extinct Dinosaur Science DOI: 10.1126/science.1186290