Tuesday, July 06, 2021

Research brief: New fossil sheds light on the evolution of how dinosaurs breathed

UNIVERSITY OF MINNESOTA

Research News

 VIDEO: USING A WELL-PRESERVED FOSSIL AND HIGH-POWERED X-RAYS, AN INTERNATIONAL TEAM INCLUDING A UNIVERSITY OF MINNESOTA RESEARCHER HAS DISCOVERED THAT NOT ALL DINOSAURS BREATHED IN THE SAME WAY. THIS VIDEO SHOWS... view more 

Using an exceptionally preserved fossil from South Africa, a particle accelerator, and high-powered x-rays, an international team including a University of Minnesota researcher has discovered that not all dinosaurs breathed in the same way. The findings give scientists more insight into how a major group of dinosaurs, including well-known creatures like the triceratops and stegosaurus, evolved.

The study is published in eLife, a peer-reviewed open access scientific journal for the biomedical and life sciences.

Not all animals use the same techniques and organs to breathe. Humans expand and contract their lungs. Birds have air sacs outside their lungs that pump oxygen in, and their lungs don't actually move. For a long time, paleontologists assumed that all dinosaurs breathed like birds, since they had similar breathing anatomy. This study, however, found that Heterodontosaurus did not--it instead had paddle-shaped ribs and small, toothpick-like bones, and expanded both its chest and belly in order to breathe.

Heterodontosaurus is the oldest dinosaur in the Ornithischian line, one of three major dinosaur groups that includes Triceratops, Stegosaurus, and other duck-billed dinosaurs. The other groups are sauropods, or longnecks, and theropods like the T-Rex.

"We actually have never known how these [Ornithischians] breathed," said Viktor Radermacher, lead author of the study and a Ph.D. student in the University of Minnesota's Department of Earth and Environmental Sciences. "The interesting thing is that Heterodontosaurus is the ancestor of this group and it has these [newly discovered] pieces of anatomy, but its descendants don't. What that means is that Heterodontosaurus is a missing link between the ancestors of dinosaurs and the bigger, charismatic species we know. This gives us a whole bunch of information and fills in some pretty glaring gaps in our knowledge of the biology of these dinosaurs."

The researchers analyzed the new Heterodontosaurus specimen with high-powered x-rays generated from a synchrotron--a giant, donut-shaped particle accelerator that spins electrons at the speed of light--at the European Synchrotron Radiation Facility (ESRF) in France. Using those x-rays, they were able to digitally reconstruct the skeleton and identify the dinosaur's unique features.

"The takeaway message is that there are many ways to breathe," Radermacher said. "And the really interesting thing about life on Earth is that we all have different strategies to do the same thing, and we've just identified a new strategy of breathing. This shows that utilizing dinosaurs and paleontology, we can learn more about the diversity of animals on Earth and how they breathe."


CAPTION

The newly discovered Heterodontosaurus tucki specimen (left), along with the researchers' digital reconstruction of the fossil (right), shows the dinosaur's unusual paddle-shaped ribs and small, toothpick-like bones.

CREDIT

Credit: Viktor Radermacher

In addition to Radermacher, the research team included Vincent Fernandez, an ESRF beamline scientist and X-Ray technician at the Natural History Museum, UK; Emma Schachner, an associate professor at Louisiana State University; Richard Butler, a professor of palaeobiology at the University of Birmingham, UK; Emese Bordy, an associate professor at the University of Cape Town, South Africa; Michael Naylor Hudgins, a grad student at the University of Alberta, Canada; William de Klerk, emeritus curator of the Department of Earth Sciences at Rhodes University in Makhanda, South Africa; Kimberley Chapelle, a postdoctoral fellow at the American Museum of Natural History in New York; and Jonah Choiniere, a professor of comparative palaeobiology at the University of the Witwatersrand, South Africa.

The research was funded by grants from South Africa's National Research Foundation (NRF) and Department of Science and Technology (DST), the Palaeontological Scientific Trust, and the Durand Foundation for Evolutionary Biology and Phycology.

Read the full paper entitled "A new Heterodontosaurus specimen elucidates the unique ventilatory macroevolution of ornithischian dinosaurs" on the eLife website.

New fossil sheds light on the evolution of how dinosaurs breathed

EUROPEAN SYNCHROTRON RADIATION FACILITY

An international team of scientists has used high-powered X-rays at the European Synchrotron, the ESRF, to show how an extinct South African 200-million-year-old dinosaur, Heterodontosaurus tucki, breathed. The study is published in eLife on 6 July 2021.

In 2016, scientists from the Evolutionary Studies Institute at the University of the Witwatersrand in Johannesburg, South Africa, came to the ESRF, the European Synchrotron in Grenoble, France, the brightest synchrotron light source, for an exceptional study: to scan the complete skeleton of a small, 200-million-year-old plant-eating dinosaur. The dinosaur specimen is the most complete fossil ever discovered of a species known as Heterodontosaurus tucki. The fossil was found in 2009 in the Eastern Cape of South Africa by study co-author, Billy de Klerk of the Albany Museum, Makhanda, South Africa. "A farmer friend of mine called my attention to the specimen" says de Klerk, "and when I saw it I immediately knew we had something special on our hands."

Fast forward some years: the team of scientists, using scans and new algorithm developed by ESRF scientists to virtually reconstruct the skeleton of Heterodontosaurus in unprecedented detail, and thus show how this extinct dinosaur breathed. "This specimen represents a turning point in understanding how dinosaurs evolved" explains Viktor Radermacher, corresponding author, South African PhD now at the University of Minnesota, US.

Not all animals use the same techniques and organs to breathe. Humans expand and contract their lungs. Birds have air sacs outside their lungs that pump oxygen in, and their lungs don't actually move. For a long time, paleontologists assumed that all dinosaurs breathed like birds, since they had similar breathing anatomy. This study, however, found that Heterodontosaurus did not--it instead had paddle-shaped ribs and small, toothpick-like bones, and expanded both its chest and belly in order to breathe.

Heterodontosaurus is one of the oldest and first-evolving Ornithischians, the group that includes favourites like Triceratops, Stegosaurus, and duckbilled dinosaurs. Heterodontosaurus lived in the early Jurassic period, about 200 million years ago, surviving an extinction at the end of the prior Triassic period. Understanding how this dinosaur breathed could also help paleontologists figure out what biological features allowed certain dinosaurs to survive or caused them to go extinct.

"We've long known that the skeletons of ornithischian dinosaurs were radically different from those of other dinosaurs," explains Richard Butler, from the School of Geography, Earth, and Environmental Sciences, University of Birmingham, UK. "This amazing new fossil helps us understand why ornithischians were so distinctive and successful", he adds.

This study is the result of a long-standing collaboration between palaeontologists based in South Africa and at the ESRF, where non-invasive techniques have been developped specifically for palaeontological studies. "You could only do this study with a synchrotron" says Vincent Fernandez, scientist at the Natural History Museum in London, UK, co-author of the study and former ESRF scientist. "The characteristics of the ESRF's X-rays, combined with its high energy beamline configuration, made scanning this complete turkey-sized dinosaur possible".

This is a perfect example of the diversity of life on Earth. "The takeaway message is that there are many ways to breathe," Radermacher said. "And the really interesting thing about life on earth is that we all have different strategies to do the same thing, and we've just identified a new strategy of breathing."

"Studies like this highlight how South Africa's fossil record once again helps us understand evolutionary origins" said senior author Jonah Choiniere, Professor at the Evolutionary Studies Institute, University of the Witwatersrand, South Africa.


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Life reconstruction of Heterodontosaurus vocalising on a cool Jurassic morning. Credit: Viktor Radermacher

CREDIT

Viktor Radermacher

Scientists Contact:

Viktor Radermacher, corresponding author, University of Mineesota, US - viktorsaurus91@gmail.com - US cell number: +1 6123254785

Whatsapp: +27 761278242

Vincent Fernandez, former scientist at the ESRF, now at the Natural History Museum, London, UK, co-author - v.fernandez@nhm.ac.uk - +33 6 95 57 68 96

Supports:

Authors Viktor Radermacher, Kimberley Chapelle, and Jonah Choiniere were supported by grants from the NRF-African Origins Platform, Centre of Excellence in Palaeosciences, and the Palaeontological Scientific Trust. South African participation in the ESRF, the European synchrotron, is supported by the NRF and DSI.


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