Dinosaur Fossil Reveals True Feather Colors

• By Sid Perkins, Science News

Another week, another colorful feathered dinosaur. Hot on the heels of a recent report identifying pigments in fossilized dino feathers and filaments (SN Online: 1/27/10), a different team of scientists says that it has mapped the full pattern of plumage sported by the oldest known feathered dinosaur.


Paleontologists first described Anchiornis huxleyi, which lived in what is now northeastern China between 151 million and 161 million years ago, in September (SN: 10/24/09, p. 8). Reports of the lithe, peacock-sized dinosaur caused quite a stir, not least because the feathered creature was older than Archaeopteryx, which is considered by many scientists to be the oldest known bird.
Now, analyses of fossil feathers from all parts of A. huxleyi’s body — reported online Feb. 4 and in an upcoming Science — provide a detailed look at the dino’s color scheme. The new findings also bolster the notion that feathers first evolved for a purpose other than flying, scientists say.
A. huxleyi had black and gray body plumage, the team’s investigations suggest. And while the long feathers on the front and side of the creature’s crest were gray, those sprouting from the top and back of its head were reddish-brown. Along with reddish-brown spots on its head and neck, A. huxleyi sported white racing stripes on its legs and its winglike forelimbs.


Paleobiologist Jakob Vinther of Yale University and his colleagues took a microscopic look at fossilized feathers at 29 sites on a specimen of A. huxleyi unearthed early last year. Some analyses focused on the small, simple feathers that covered the creature’s body and skull, and others targeted the longer, more complex feathers that adorned its forelimbs, legs and feet. “There was hardly any part of the creature that wasn’t feathered,” Vinther notes.
Almost all of the feathers the team scrutinized contained well-preserved remnants of pigment-bearing structures called melanosomes. Feathers lacking melanosomes were probably white, the researchers note. By comparing the size, shape, density and arrangement of melanosomes in each fossil feather with those in variously colored feathers of modern birds, the team then sketched out what A. huxleyi looked like. “Using those comparisons, we can reliably predict [the creature’s] color and map the whole animal,” Vinther says.
The team’s analyses “reveal an enormous array of information,” says Michael Benton, a paleontologist at the University of Bristol in England. The black-and-white bars on A. huxleyi’s forelimbs, as well as its colorful crest, are reminiscent of similar features in modern birds, he adds.
Knowing when color appeared in feathers or filaments may help solve the conundrum of why those structures evolved in the first place, Benton says. After all, he notes, A. huxleyi’s feathered forelimbs weren’t sufficiently large enough to carry the creature’s weight in flight. “What’s the function of half a wing?” he asks. The fact that feathers appear in the fossil record long before flight-capable birds suggests that feathers initially served a behavioral function, possibly one related to sending visual signals, and only later began to serve an aerodynamic function.
Philip J. Currie, a paleontologist at the University of Alberta in Edmonton, Canada, agrees: “Ancient creatures didn’t just sprout feathers and start flying. The feathers were there for another reason first.” Fossils reveal that dinosaurs often had very large eyes and sizable optic lobes in their brains. “Dinosaurs were very visual animals, just like birds are,” he adds.
Bold patterns of plumage, such as those seen in A. huxleyi, could have served any of a number of functions, Vinther and his colleagues speculate. Besides communicating to members of its own species — a “come here, cutie” to members of the opposite sex, say, or a “back off” message to rival suitors — a quick flash of boldly colored plumage could startle an attacking predator or flush prey out of hiding, the researchers say.

Images: 1) © 2010 National Geographic. 2) Jakob Vinther/National Geographic. 3) Jakob Vinther/National Geographic.

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The First Hints Of A Dinosaur's True Colors

by Nell Greenfieldboyce

from: http://www.npr.org/

Enlarge Chuang Zhao and Lida Xing

An artist's rendition of two Sinosauropteryx dinosaurs, showing their short, bristle-like feathers along the midline of the head, neck, back and around the tail, forming irregular stripes.

Scientists have found evidence of some of the original coloration of a dinosaur that lived about 125 million years ago, showing that it had rings of orange-brown bristly feathers around its tail.

Fossils have revealed a lot about the lives of dinosaurs, but researchers always used to think that the fossil record couldn't show what color they were. "This was the one point at which we had to give up," says paleontologist Mike Benton at the University of Bristol in the United Kingdom, who explains that fossils tend to preserve an animal's hard parts, like bones and teeth, and not soft parts like skin.

But feathers are made of tough proteins. "And, in fact, they can survive even in conditions where other internal organs, you know, muscles and guts and brains and so on, will disappear," says Benton.

That created the possibility of learning something about what colors could be found in the primitive feathers of early birds and recently discovered feathered dinosaurs.

Unfortunately, these fossilized, ancient feathers just look like rock to the naked eye, because of the way they were preserved. "When you look at the feathers, you don't know what the colors were. The feathers are a mixture of brownish colors," says Benton. "They're just preserved either as sort of dirty, whitish, beige kind of color and a kind of darker, equally dirty kind of brownish color."

Enlarge The Nanjing Institute

The fossil of a small Chinese theropod dinosaur, Sinosauropteryx.

Clues About The Original Color

But Benton and his colleagues thought they could get clues about the original color by looking at tiny structures inside these fossilized feathers.

After all, they knew that in the feathers of living birds, some color comes from pigments called melanins. And inside of a hair or a feather, "the melanin is actually contained within a kind of capsule," says Benton.

The shape of the capsule depends on the color. "The black or dark brown kind of melanin goes into a somewhat sausage-shaped capsule," says Benton, while a reddish-brown kind of melanin goes into a more rounded capsule shaped like a ball.

With this in mind, the researchers used a sophisticated, powerful microscope to peer inside primitive feathers on a turkey-sized dinosaur called Sinosauropteryx. "It's a flesh-eater. It's got sharp little teeth in its mouth, and it's got grabby little hands," says Benton. "It's a two-legged dinosaur, so very slender limbs. It's got a sort of straightish backbone and a long thin tail."

Fossils show that this tail was ringed with dark bands of primitive feathers that look like bristles. And inside these bristles, Benton and his colleagues found melanin capsules in the shape associated with the orange-brown color.

"These dark stripes, as far as we can tell, were exclusively ginger, and so this early dinosaur with its long thin tail had ginger and white stripes up the tail," says Benton.

'Watertight Evidence Of The Original Color'

He says they assume the tail must have been completely covered with primitive feathers, with alternating orange-brown and white stripes. The white feathers would not have contained any melanin capsules, which means they would have had less structural strength and would have decayed rather than being preserved in the fossil.

"For the first time ever, we have evidence, we believe fairly watertight evidence, of the original color," says Benton.

The researchers also looked inside feathers from fossils of the early bird Confuciusornis and found that this species appears to have had patches of white, black and orange-brown coloring.

Enlarge Jim Robbins

The Sinosauropteryx was a turkey-sized, flesh-eating dinosaur that scientists believe had primitive feathers and dark rings around its tail.

Benton's team reported all of these findings in the journal Nature. Other paleontologists said the work was an impressive feat.

From Artistry To Science

"This is a really exciting result," says Richard Prum, an evolutionary ornithologist at Yale University. He and his colleagues had previously shown that melanin capsules fossilize very well in feathers. "But that work was based on much more recent fossil bird feathers," says Prum, adding that this new study extends the work to much older specimens from feathered dinosaurs.

"This study begins to bring the colors of dinosaurs out of the realm of artistry and into the realm of science," says Thomas Holtz of the University of Maryland.

But Holtz says this approach will only be possible for feathers and maybe scales on those dinosaurs that are extremely well-preserved in fossils. That doesn't include a famous one that he studies — Tyrannosaurus rex.

"I would love to know if Tyrannosaurus was green or brown or, you know, chartreuse," says Holtz. But he doesn't think that's going to be possible. "It's unlikely that I'll ever know or that anyone will ever know the colors of some of our favorite dinosaurs."

For these extinct creatures, at least, it looks like artists trying to create images of a long-lost world will continue to be limited only by their imagination, and not by science.

Listen Discovering Dinosaur Color From Fossilized Feathers

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Will We Clone a Dinosaur?

If you use DNA taken from its myriad wing descendants, the idea is not as farfetched as it first appears

By MATT RIDLEY

The short answer is no. The slightly longer answer is definitely not. The Jurassic Park idea „ amber, insects and bits of frog dna „ would not work in a million years, and it was by far the most ingenious suggestion yet made for how to find dinosaur genes. Cloning a mammoth„flash frozen for several thousand years „ might just prove feasible one day. But dinosaurs, 65 million years old? No way.

It is only when you ask the question the third time that you begin to see a glimpse of an affirmative answer. Start with three premises. First, dinosaurs did not die out; indeed there are roughly twice as many species of their descendants still here on Earth as there are mammals, but we call them birds. Second, dna is turning out to be a great deal more "conserved" than anybody ever imagined. So-called Hox genes that lay down the body plan in an embryo are so similar in people and fruit flies that they can be used interchangeably, yet the last common ancestor of people and fruit flies lived about 600 million years ago.

Third, and most exciting, geneticists are finding many "pseudogenes" in human and animal dna „ copies of old, discarded genes. It's a bit like finding the manual for a typewriter bound into the back of the manual for your latest word-processing software. There may be a lot of interesting obsolete instructions hidden in our genes.

Put these three premises together and the implication is clear: the dino genes are still out there. So throw your mind forward a few decades, and try out the following screenplay. A bunch of bioinformatics nerds in Silicon Valley, looking for an eye-catching project to showcase the latest ipo, decide to try to recreate the genome of a dinosaur. They bring together a few complete bird genomes„complete dna texts from the cells of different birds „ and start mapping the shared features. The result is a sort of prototype genome for a basic bird.

Then they start fiddling with it: turning on old pseudogenes; knocking out the genes for feathers and putting back in the genes for scaly skin; tweaking the genes for the skull so that teeth appear instead of a beak; shrinking the wings, keel and wishbone (ostrich genes would be helpful here); massively increasing size and sturdiness of the body; and so on. Pretty soon they have the recipe for a big, featherless, wingless, toothy-jawed monster that looks a little like a cross between a dodo and a tiger.

They might not have to fix that many genes „ just a few hundred mainly developmental ones. The genes for the immune system, for memory mechanisms and the like would all be standard for a vertebrate. To fine-tune the creature, they could go fishing in other bird genomes, or perhaps import a few ideas from lizards and turtles.

Remember, at this stage nothing has left the computer; all they have is a dna recipe. But by the end of this century, if not sooner, biotechnology will have reached the point where it can take just about any dna recipe and read off a passable 3-D interpretation of the animal it will create. After a massive amount of digital trial and error, the nerds reckon they have a recipe for a creature that would closely resemble a small, running dinosaur, such as Struthiomimus ("the ostrich mimic").

The rest is as easy as Dolly the sheep: call up a company that can synthesize the genome, stick it into an enucleated ostrich ovum, implant the same in an ostrich and sit back to watch the fun. Of course, there will be teething troubles - literally. Or somebody might have forgotten to cut out the song bird's voice genes, so the first struth chirps like a sparrow. Or maybe the brain development did not quite hang together and the creature is born incapable of normal movement. As this suggests, the first such experiment will almost certainly produce a bit of a Frankenstein's monster, and the whole idea may well therefore be cruel and unethical, in which case, let us hope it never happens. But that is not the same as saying it will be impossible.

And it just might prove much easier than I am implying. Who knows? Rusty old pseudogenes left over from the great sauropods may still be intact, hidden somewhere in the genes of a hummingbird.