UCC discovery of 125m-year-old dinosaur dandruff
The research by UCC palaeontologists reveals the first evidence of how dinosaurs shed their skin.
UCC’s Maria McNamara led the study, in collaboration with her postdoctoral researcher Chris Rogers; Andre Toulouse and Tara Foley, also from UCC; Paddy Orr from UCD, and a team of palaeontologists from the UK and China.
For the study, which was published in the journal Nature Communications, they studied the fossil cells, and dandruff from modern birds, with powerful electron microscopes. Just like human dandruff, the fossil dandruff is made of tough cells called corneocytes, which in life were dry and full of the protein keratin.
The study suggests that this modern skin feature evolved sometime in the late Middle Jurassic, around the same time as a host of other skin features evolved.
It is the first evidence of how dinosaurs shed their skin. The feathered dinosaurs studied — Microraptor, Beipiaosaurus, and Sinornithosaurus — clearly shed their skin in flakes, like the bird Confuciusornis, studied by the team, and also like modern birds and mammals, and not as a single piece or several large pieces, as in many modern reptiles.
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 not for long periods.
Dr McNamara said: “The fossil cells are preserved with incredible detail, right down to the level of nanoscale keratin fibrils.
“What’s remarkable is that the fossil dandruff is almost identical to that in modern birds — even the spiral twisting of individual fibres is still visible.”
“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.
The co-author of the research, Mike Benton from the University of Bristol’s School of Earth Sciences, said: “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.”
