The colour of dinosaur feathers identified
The press release is here.
The colour of some feathers on dinosaurs and early birds has been identified for the first time, reports a paper published in Nature this week.
The research found that the theropod dinosaur Sinosauropteryx had simple bristles - precursors of feathers - in alternate orange and white rings down its tail, and that the early bird Confuciusornis had patches of white, black and orange-brown colouring. Future work will allow precise mapping of colours and patterns across the whole bird.
Mike Benton, Professor of Palaeontology at the University of Bristol, said, "Our research provides extraordinary insights into the origin of feathers. In particular, it helps to resolve a long-standing debate about the original function of feathers - whether they were used for flight, insulation, or display. We now know that feathers came before wings, so feathers did not originate as flight structures.
"We therefore suggest that feathers first arose as agents for colour display and only later in their evolutionary history did they become useful for flight and insulation."
The team of palaeontologists from the University of Bristol, UK, the Institute of Vertebrate Paleontology and Paleoanthropology (IVPP) in Beijing, University College Dublin and the Open University report two kinds of melanosomes found in the feathers of numerous birds and dinosaurs from the world-famous Jehol beds of NE China.
Melanosomes are colour-bearing organelles buried within the structure of feathers and hair in modern birds and mammals, giving black, grey, and rufous tones such as orange and brown. Because melanosomes are an integral part of the tough protein structure of the feather, they survive when a feather survives, even for hundreds of millions of years.
This is the first report of melanosomes found in the feathers of dinosaurs and early birds. It is also the first report of phaeomelanosomes in fossil feathers, the organelles that provide rufous and brown colours.
These discoveries confirm the substantial body of evidence that suggests birds evolved through a long line of theropod (flesh-eating) dinosaurs. It also demonstrates that the unique assemblage of characters that make a modern bird - feathers, wings, lightweight skeleton, enhanced metabolic system, enlarged brain and visual systems - evolved step-by-step over some 50 million years of dinosaur evolution, through the Jurassic and Cretaceous periods.
"These discoveries open up a whole new area of research", said Benton, "allowing us to explore aspects of the life and behaviour of dinosaurs and early birds that lived over 100 million years ago.
"Furthermore, we now know that the simplest feathers in dinosaurs such as Sinosauropteryx were only present over limited parts of its body - for example, as a crest down the midline of the back and round the tail - and so they would have had only a limited function in thermoregulation.
"Feathers are key to the success of birds and we can now dissect their evolutionary history in detail and see how each feather type - and the fine detail of feather structure - was acquired through time. This will link with current work on how the genome controls feather development."
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A zebra finch, and one of its feathers, showing sausage-shaped eumelanosomes in the black parts of the feather and spherical phaeomelanosomes in the orange part of the feather. Photo of bird is Wikimedia Commons, by Peripitus, http://en.wikipedia.org/wiki/File:Taeniopygia_guttata_-_front_view_-_dundee_wildlife_park.jpg; feather and melanosomes copyright © University of Bristol; bird specimen and feather courtesy of the National Museum of Ireland, Natural History Division.
The ancient bird Confuciusornis from 125-million-year-old lake sediments of the Jehol Group in NE China, showing dark impressions of feathers and soft tissues in the body region, and paler impressions of wing feathers and the long narrow tail feathers. Samples from different parts of the body show sausage-shaped eumelanosomes (top), presumably indicating black parts of the feathers, and spherical phaeomelanosomes (bottom), presumably in orange parts of the feathers. Scale bars on black-and-white photos represent 2 microns. Photo of fossil is copyright © Institute of Vertebrate Paleontology and Paleoanthropology, Beijing; melanosome images (right) copyright © University of Bristol.
The small flesh-eating Chinese theropod dinosaur Sinosauropteryx, a complete specimen from head (right) to tip of tail (top left), in the Nanjing Institute. Short, bristle-like feathers run along the midline of the head, neck, and back, and all round the tail, forming irregular stripes. We sampled from a 'dark' stripe near the base of the tail (marked with arrow), and found only phaeomelanosomes (top right) in these feathers, indicating that the dark stripes were orange-brown in life. The pale-coloured stripes contain no melanosomes, so were probably white. Photo of fossil is from The Jehol Biota book, authored by scientists from IVPP, the Nanjing Institute, and elsewhere;
melanosome image (top right) copyright © University of Bristol.
Reconstruction of two Sinosauropteryx, sporting their orange and white striped tails. The orange colour is demonstrated by the presence of the colour-bearing organelles called phaeomelanosomes, found packed densely in the filament-like tail feathers. The pale stripes do not carry melanosomes, suggesting they were white. Original artwork by Chuang Zhao and Lida Xing, copyright © Chuang Zhao and Lida Xing.
Reconstruction of Sinosauropteryx, sporting its orange and white striped tail. The orange colour is demonstrated by the presence of the colour-bearing organelles called phaeomelanosomes, found packed densely in the filament-like tail feathers. The pale stripes do not carry melanosomes, suggesting they were white. Original artwork by James Robins, copyright © James Robins. Further information from http://www.jr-illustration.co.uk/.
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The paper: Zhang, F., Kearns, S.L, Orr, P.J., Benton, M.J., Zhou, Z., Johnson, D., Xu, X., and Wang, X. 2010. Fossilized melanosomes and the colour of Cretaceous dinosaurs and birds. Nature 463, 1075-1078 (doi:nature08740.3d). pdf. Supplementary data.
This research was funded by the Chinese Academy of Sciences, the Ministry of Science and Technology of China (MSTC), and the National Natural Science Fund of China (NSFC) in Beijing, and the Natural Environment Research Council (NERC) in the UK.
Among some 400 or more news articles, we note a few:
- BBC News by Victoria Gill
- National Geographic by Chris Sloan
- New York Times by Carl Zimmer
- National Public Radio, with audio, by Nell Greenfieldboyce
- CNN, with TV report online, by Phil Han
- Science by Richard Stone
- Nature News by Matt Kaplan, and Nature podcast for 28th January, 2010
- Science Now by Sverker Lundin
- Scientific American by Katherine Harmon
- Eurekalert, in English and in Chinese, by Kevin Holden
- Natural History Museum London
- Channel 4 News
- US News & World Report by Sid Perkins
- New York Daily News by Sherryl Connelly
- Times Online by Hannah Devlin
- The Guardian by Ian Sample
- The Independent by Steve Connor
- The Telegraph by Richard Alleyne
- Daily Mail by David Derbyshire
- ABC News by Seth Borenstein
- RTE, with Paddy Orr TV film
- Irish Times by Dick Ahlstrom
- Irish Independent by Shane Hickey
- Yahoo News/ AFP by Richard Ingham
- NERC podcast (February 2011)
- 'Feathered dinosaurs' by Manabu Sakamoto, in Discovering Dino World, Pen books (July 2011)