Flake news: dinosaurs had dandruff
Paleobiologist Dr Maria McNamara loves fossils for the fascinating insights they can yield about ancient life
You research fossils. Was that an interest you developed as a child?
“I was never one of those kids that was interested in dinosaurs, but I wanted to know all about the world. I loved wildlife books and in atlases I would read the pages at the start about the interior of the earth.
I’m from Clonmel, and when we went to stay with my granny in north Tipperary in the summers she would send us out with a net and tell us to find three different types of grasshopper, or she would tell us to find particular types of wildflowers. We’d go off roaming through the fields to find these things; then we had to identify what we brought back. I loved all that.
You have done a lot of work on “soft” fossils. What are they?
When tissues of animals get preserved as fossils they are effectively turned into a form of stone. You can see the structures of bones, but sometimes the soft tissues also get preserved, parts of skin and muscles and feathers and hair.
In the mid-2000s I looked 10-million-year-old salamander and frog fossils in Spain and we analysed the muscles, skin and internal organs. We also found fossilised bone marrow for the first time in the frogs.
What are you working on now?
I’ve recently been looking at feather and skin development in dinosaurs, reptiles and birds. A few years ago myself and colleagues described a plant-eating dinosaur fossilised in Siberia that had three different types of feather: bristles, ribbon-like feathers and other filament-like structures.
And just last month we published a paper describing dinosaur “dandruff” for the first time.
Yes, we identified small flakes of the outer layer of the skin from three feathered dinosaurs and a fossil bird from around 125 million years ago. We could see that the fossil cells were jam-packed with fibres of keratin, a tough protein we find in skin, nails and claws. The skin of modern birds, on the other hand, is not as full of keratin and it contains lots of fats that help them to keep cool as they fly. So the implication here is that the animals that had been fossilised didn’t need to cool down. It also seems that the fossilised animals shed flakes of skin much like birds do, rather than all in one go like reptiles do.
How did you feel when you found that out?
That study was really sweet, actually. I’ve been working on it with colleagues in UCC, University College Dublin, the UK and China for several years. We had been looking at the feathers of the dinosaurs, and we noticed these flakes of skin in the samples but we were struggling to see them properly in enough numbers. So we spent hundreds of hours on the electron microscope looking through the samples to get views of the helical keratin fibres in the flakes. We really put in the hard years and it was very satisfying to get the results.
What do you think you might have been if you hadn’t become a scientist?
When I was in school I remember crying when I found out I could study only one thing at university. I wanted to study art, music, English and science, and to have to pick one was terrible. If I retired from science I might like to do art or music, or forage for jam. There are too many things in this world to have to choose one.”