IRISH scientists have discovered 125 million year-old dandruff in dinosaur fossils - offering a revolutionary insight into how the ancient creatures shed and renewed their skin.
The discovery was made by University College Cork (UCC) palaeontologist Dr Maria McNamara and her team after years of study of the fossils of feathered dinosaurs and birds.
The fossils studied included those of the remarkable dinosaurs, Microraptor, Beipiaosaurus and Sinornithosaurus.
Using powerful electron microscopes, they studied fossil cells as well as dandruff from modern birds - and discovered that 'dino dandruff' almost precisely matches the dandruff in modern birds which forms part of their skin renewal process.
Their findings are publishing today in the prestigious science journal, Nature Communications.
“The fossil cells are preserved with incredible detail – right down to the level of nanoscale keratin fibrils," Dr McNamara said.
"What is remarkable is that the fossil dandruff is almost identical to that in modern birds – even the spiral twisting of individual fibres is still visible."
As in human dandruff, the fossil dandruff is made of tough cells called corneocytes.
In life they are dry and full of the protein keratin.
Dr McNamara's study has suggested that this modern skin feature evolved sometime in the late Middle Jurassic era around the same time as a host of other skin features evolved.
"There was a burst of evolution of feathered dinosaurs and birds at this time, and it’s exciting to see evidence that the skin of early birds and dinosaurs was evolving rapidly in response to bearing feathers," she said.
Dr McNamara led the study, in collaboration with her postdoctoral researcher Dr Chris Rogers; Dr Andre Toulouse and Tara Foley, also
from UCC; Dr Paddy Orr from UCD and an international team of palaeontologists from the UK and China.
Remarkably, their discovery is the first evidence confirmed as to how dinosaurs shed their skin.
The feathered dinosaurs studied shed their skin in flakes, like the early bird Confuciusornis studied by the team and also modern birds and mammals.
In contrast, modern reptiles shed their skin in a single piece or in several large pieces.
The study co-author Professor Mike Benton, from the University of Bristol’s School of Earth Sciences, said it was a remarkable finding.
“It’s unusual to be able to study the skin of a dinosaur, and the fact this is dandruff proves the dinosaur was not shedding its whole skin like a modern lizard or snake but losing skin fragments from between its feathers,” he said.
Modern birds have very fatty corneocytes with loosely packed keratin, which allows them to cool down quickly when they are flying for extended periods.
The corneocytes in the fossil dinosaurs and birds, however, were packed with keratin, suggesting that the fossils didn’t get as warm as modern birds, presumably because they couldn’t fly at all or for as long periods.