Decoding dinosaurs’ true colours

Scientists have been trying to decipher the colours of feathered dinosaurs by studying pigmented structures called melanosomes in the animals’ fossilised plumes. These studies have launched a renaissance of correctly coloured dinosaur artwork, but a team of palaeontologists has now questioned the accuracy of these reconstructions. Melanosomes are organelles typically present in the cells of the skin, hair and feathers. Reddish-brown ones tend to be shaped like meatballs; black or grey ones are usually sausage-shaped.

Jakob Vinther, a molecular palaeobiologist at the University of Bristol, UK, started using the shape and distribution of the organelles to infer the colour of prehistoric feathers back in 2007. He has since used the technique to paint a black-and-grey body and red crest on the small dinosaur anchiornis huxleyi, a grey-and-red coat on the giant penguin inkayacu paracasensis and a glossy black sheen on the four-winged microraptor.

But Maria McNamara, now also at the University of Bristol, says that some of these reconstructions may be inaccurate. McNamara and her colleagues mimicked the process of fossilisation by placing modern bird feathers in an autoclave, a machine that sterilises lab equipment with 250 times atmospheric pressure and temperatures of 200-250 degrees Celsius. McNamara says that the extent of the distortions depends on how the feathers are preserved.

Those from hotter and deeper deposits, such as the Chinese sediment that Anchiornis came from, would be more heavily deformed than those from shallower regions. It should be possible to account for these changes and to revise the colours previously assigned to such dinosaurs, McNamara says. Vinther doubts that anchiornis’s colours need to be revised, because he based those on the ratio of the melanosomes’ length to width.
McNamara argues that palaeontologists now need to understand how far melanosomes have to shrink before the colour of the feather changes.

Ed Yong

Boneworms’ secret revealed

Boneworms are gutless and mouthless, but somehow they live off the carcasses of whalebones. Researchers say that the worms produce and secrete an acid that can dissolve bone. “Trapped inside is collagen and lipids, and we think the worms absorb this,” said Martin Tresguerres, a comparative physiologist at the University of California, San Diego, and one of the researchers involved in the study, which appears in The Proceedings of the Royal Society B. Tresguerres and his colleagues discovered that boneworms have enzymes called proton pumps on the part of their body that bores into whalebone.

Sindya N Bhanoo


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