Rare dinosaur skin offers insights into evolution

By Victoria Schramm, U of S Posted: December 10, 2019 10:30 a.m.

Dr. Mauricio Barbi holding a piece of hadrosaur skin.
Dr. Mauricio Barbi holding a piece of hadrosaur skin. Photo: U of R Photography

Mauricio Barbi has loved dinosaurs for as long as he can remember and dreamed of one day being a paleontologist. “When I was a kid, I loved space, stars, and dinosaurs,” he said. 

Fast-forward a few years, and Barbi, who is an experimental high energy particle physics professor at the University of Regina, is trekking through the Alberta Badlands alongside the famous paleontologist Dr. Philip Currie, Faculty of Science, University of Alberta, whose professional life became the inspiration for characters in the Jurassic Park movies. During this fieldwork, he also met Australian paleontologist and senior lecturer at the University of New England, Dr. Phil Bell, who had recently found a well-preserved hadrosaur. When he joined Bell in the excavations, Barbi was shocked and thrilled by what they discovered. 

“Understanding what life used to be like on our planet is extremely important, but very difficult to piece together. When you look far back in time, there isn’t much left over. If you’re lucky, there are bones left, but even those fossilize into rock over millions of years,” he said. 

On the dig, the team of scientists discovered what they initially thought was an imprint of dinosaur skin. What they actually found was something much rarer—patches of well-preserved 3-dimensional fossilized skin from a 72-million-year-old hadrosaur dinosaur.

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The Falls site where the hadrosaur was being excavated. Photos courtesy Dr. Barbi.

 

“I wouldn’t have expected to find that in a million years,” said Barbi. “This sort of thing is extremely rare to find and the condition of preservation is absolutely astonishing.” 

At first, they did not know what they had found. “When I first held the sample, I noticed it was three dimensional and not likely an imprint. With an electron microscope, I could tell that there was an organized distribution of carbon and it seemed to be in layers, but I was suspicious,” he commented. 

He and his colleagues then went to the Canadian Light Source (CLS) at the University of Saskatchewan and used non-destructive synchrotron light to analyze their sample at the atomic and molecular level. 

“It was a no-brainer for me,” said Barbi, who works on neutrino physics experiments in different parts of the world. “The CLS provides dense beams of radiation that comes in several types of wavelengths. With x-rays, you can look at very tiny structures like atoms, with infrared you can look at larger structures like organic molecules. The CLS can provide these capabilities all in one place and produce a lot of data in a short interval of time.” 

Using several beamlines and techniques, it became clear that the sample had layers made of small, semi-circle structures that very much resembled cells.

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A piece of the hadrosaur skin. Photo: U of R Photography

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

The team also used optical microscopy to compare the dinosaur skin with the skin of modern animals, including a crocodile, rat and chicken. 

“The skin was beautifully preserved at the microscopic level,” Bell said. “We found clear resemblance between the dinosaur and the crocodile. In particular, the layer of skin that had fossilized corresponded to the keratinous layers of the scale in the crocodile; a layer called the stratum corneum.” 

Directly comparing the layout of cell layers in dinosaur skin with those of modern animals is a world first. 

“We study evolution based on what animals looked like. We can guess how things were based on bones and impressions of ligaments and imprints left in materials such as mud, but this was the first time we could directly compare the layout of cell layers in dinosaurs to living creatures,” said Barbi. “This helps us understand how animals have evolved. It’s astonishing. 

“What is funny about this research is that when I started doing this, I was not looking for cell layers. I was looking for pigments to see if we could tell the colour of that dinosaur. Then, we found something much better. 

“It opened our eyes to the possibilities. We need to look more carefully at other well preserved specimens to see what is actually there. I hope this work will send a message to other scientists

to look more carefully at these kinds of things and do a more in-depth analysis, using different techniques.” 

Barbi and colleagues also tried to piece together what had happened to this dinosaur and how its skin was so well preserved. 

“The environment in which the dinosaur was found had a lot of crystallized plants,” Barbi commented. This helped to explain what a herbivore was doing there. Also, the region had a river and the dinosaur was likely partially covered by water during its decay. 

Water tends to slow decay because there is less oxygen for bacteria to feed on. “The specimen also showed evidence of mud associated with the skin, which can help in the mummification of animals,” Barbi said. “Iron in the muddy sediment likely helped in the preservation of the tissue.” 

By piecing together the puzzle of what happened millions of years ago, Barbi hopes we can also learn more about the future of our planet. In the process, he gets to fulfill his childhood wish to work with dinosaur fossils. 

“I used my knowledge in physics and all of a sudden I was making discoveries in paleontology and doing field work and working alongside the people I admired,” he said. “It has been a dream come true.” 

“Now, I want to go to Mars,” said Barbi. “It probably will never happen, but you never know.” 

This international collaboration involved researchers from the CLS; Universities of Saskatchewan, Regina, and Alberta; University of New England, in Australia; and Università di Bologna, in Italy. They used several beamlines at the CLS, including SM, SXRMB, VESPERS, BMIT and MidIR to collect data about their sample. The results of this CLS analysis were published in the peer reviewed journal PeerJ in October 2019. 

The paper, Barbi M, Bell PR, Fanti F, Dynes JJ, Kolaceke A, Buttigieg J, Coulson IM, Currie PJ.2019. Integumentary structure and composition in an exceptionally well-preserved hadrosaur (Dinosauria: Ornithischia) PeerJ 7:e7875 https://doi.org/10.7717/peerj.7875 can be found at: https://peerj.com/articles/7875/ 

As of November 2019, this paper was in the top five per cent of all research outputs scored by Altmetric.