A fossil feather of Archaeopteryx, preserved in limestone, is the first specimen of the winged dinosaur ever found. Researchers used it to determine the animal’s feather colour, which in turn provided clues about its potential for flight.
Credit: Museum für Naturkunde Berlin
The iconic Berlin specimen of Archaeopteryx.
Credit: Museum für Naturkunde Berlin
SYDNEY: Archaeopteryx, a 150 million-year-old raven-sized dinosaur, had black feathers on its wings that were structurally identical to those of modern birds, researchers have reported.
Since the discovery of Archaeopteryx 150 years ago, scientists could only guess at its colouring. Today, a study published in Nature Communications describes how a new analytic approach has been applied to a fossilised Archaeopteryx feather to reveal that its original colour was black, and its structure was tough and durable enough for flight.
"This is definitely a new, emerging science, and something that will be a standard for analysing the colours of dinosaurs and extinct birds in the future," said lead author Ryan Carney from Brown University in the U.S. "No one had ever looked this closely at an Archaeopteryx's feather before - it shows that modern flight feathers had evolved as early as 150 million years ago."
Discovering colour in Archaeopteryx
Since the first Archaeopteryx specimen was described in 1861, scientists have puzzled over what this half-dinosaur, half-bird looked like and how it moved. Over the past 150 years, the myriad recreations of the species have sported an array of red, green, blue, grey and burnt copper plumage, and debate has raged over whether it was capable of powered flight or was simply a glider.
While scientists have been finding melanosomes - pigment granules that contain melanin, the most common light-absorbing pigment - in fossilised feathers for years, until recently they have been misidentified as bacteria due to their similar, sausage-like shape.
But in 2006, co-author of the current study Jakob Vinther from Brown University discovered that melanin existed in the preserved ink sac of a fossilised squid, which led him to consider the possibility that the sausage-shaped structures previously found in fossil feathers were actually melanosomes after all. "I realised that I had opened up a whole new chapter of what we can do to understand the nature of extinct feathered dinosaurs and birds," Vinther said.
Archaeopteryx on a nanoscale
Using the first Archaeopteryx specimen ever described - a preserved feather unearthed in 1861 by German palaeontologist Hermann von Meyer near Solnhofen in Germany - the researchers attempted to image the tiny melanosomes.
After two unsuccessful attempts, Carney's team used a more powerful type of scanning electron microscope at the Carl Zeiss Laboratory in Oberkochen, Germany. This technique allowed them to view the microstructure of the ancient feather, right down to the individual melanosomes, which were roughly 1 micron long and 250 nanometres wide. "We didn't expect to find such exceptional preservation of the feather's microstructure," said Carney.
The team then statistically compared the Archaeopteryx's melanosomes to those of 87 modern bird species and found that the ancient feather was likely to have been black, with a 95% certainty.
Ancient feathers identical to modern feathers
The researchers also examined the feather's barbules, which are tiny, rib-like appendages that contain the melanosomes, and found that they were identical to those of modern birds, overlapping and interlocking like zippers to give feathers rigidity and strength.
"The Archaeopteryx feather is a flight feather, and we know that it was black and had an aerodynamic function. Black pigmentation, by virtue of the fact that melanin is such a robust polymer, has previously been found to make feather keratin harder by approximately 40%, and also thicker," said Carney, who added that melanosomes protect the feathers against abrasion caused by air particles and the motion of repetitive flight.
Not only did the analysis prove that Archaeopteryx had feathers that were strong and durable, but the researchers found that the structure of the barbules and the alignment of the melanosomes inside them are identical to those found in modern birds.
A flapper or a glider?
While Carney's research does show that Archaeopteryx had robust feathers perfect for flying or gliding, it does not indicate whether the species was a flapper or a glider. "The melanisation would certainly have made the feather stronger, but it does not prove that it was a flapper," he said.
Michael Lee from the University of Adelaide in South Australia, who was not involved in the study, said that not only does this study indicate that the middle section of the Archaeopteryx's wing was covered in black feathers, it also might resolve the debate over whether this isolated feather really belonged to Archaeopteryx.
"Previous researchers have compared the isolated feather to the main flight feathers on Archaeopteryx (on the trailing edge of the wings) and noted it was smaller and less elongate - thus suggesting it might not belong to Archaeopteryx," he said. "The new study instead proposes that the isolated feather comes from the centre of the wing, and its size and shape is much more consistent with this interpretation. Thus, the new study demonstrates the feather is the right size and shape to belong to Archaeopteryx.
Archaeopteryx feather colour and structure revealed
How useful is that information for the ordinary peopel of a country???
I do mean that Research on that Nonsens shout come to an end finally.
That,s my opinion.
Nonsens...
Your opinion was poorly expressed and full of spelling errors. A proper education would help you understand the value of scientific research. That's my opinion.