杏吧原创

听

A mummified dinosaur has skin so well preserved that the remains of blood vessels and pigment can be seen, and analysis of the pigment suggests that the animal had dark grey skin. However, it is possible that the dinosaur鈥檚 skin contained other pigments that haven鈥檛 been preserved.

While paintings of dinosaurs often show them with brightly coloured skin, we actually know very little about their true colours. Most dinosaurs are only known from bones and teeth, and in the few cases where their skin has been preserved, it has rarely been possible to detect pigment molecules. We know more about the colour of early birds听because feathers are more frequently conserved.

Matteo Fabbri and Jasmina Wiemann at Yale University in New Haven, Connecticut, and their colleagues studied a mummified hadrosaur, or duck-billed dinosaur, which had preserved skin on its flank. When they examined thin slices of the skin, they discovered globules that look like preserved cells and fragments of blood vessels. The skin was unusually thin for such a large animal, and surprisingly similar to that of birds 鈥� even though hadrosaurs weren鈥檛 that closely related to them.

Shades of grey

Wiemann, an expert on fossilised molecules who previously found that some dinosaurs laid blue eggs, chemically analysed the material. She found that some original molecules were preserved, in degraded form.

鈥淯ntil now, we saw skin from a morphological perspective, but now we know these kinds of fossils also contain molecular information,鈥� says Fabbri.

Crucially, the skin contained small granules containing eumelanin: a pigment that creates a dark grey colour. If eumelanin was the only pigment the hadrosaur possessed, it would have had grey skin like that of a rhinoceros or elephant.

However, Fabbri emphasises that the hadrosaur may have had other pigments that were destroyed during fossilisation, so we can鈥檛 be sure it was grey. 鈥淲e can rule out brown or reddish,鈥� he says, because reddish pigments contain sulphur, and there was no sulphur in the pigment-containing granules within the dinosaur skin. But other colours like green, orange, blue or yellow can鈥檛 be eliminated.

If the hadrosaur really was grey, it would make sense, says Fabbri, because they were large herbivores and moved in herds, a little like today鈥檚 grey-skinned elephants.

It is unlucky that there wasn鈥檛 skin preserved on the head, says Fabbri, as hadrosaur heads had elaborate ornamentation and may have been more colourful than the rest of the body.