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A team of paleontologists and mechanical and biomedical engineers compared CT scans of fossilized bones from hadrosaurs and other dinosaurs with bones from extinct and living mammals and found that the trabecular bone architecture of dinosaurs was only able to support heavy weight (up to 47,000 kg). and different from that of mammals and birds.
Reconstruction of the life of Kamuysaurus japonicus, a species of hadrosaur (duck-billed) dinosaur that lived about 72 million years ago (Cretaceous period) in present-day Japan. Image Credit: Kobayashi et al, doi: 10.1038 / s41598-019-48607-1.
The largest terrestrial dinosaurs were huge creatures whose body mass placed massive gravitational charges on their skeletons.
Previous studies have investigated bone strength and the biomechanics of dinosaurs, but the relationships between their trabecular bone architecture and mechanical behavior have not been investigated until now.
“The structure of the trabecula, or cancellous bone that forms inside the bones we studied, is unique in dinosaurs,” said study co-author Dr Tony Fiorillo, paleontologist in the Department. of Huffington Earth Sciences at Southern Methodist University.
“Trabecular bone tissue surrounds the small spaces or holes in the inner part of the bone, like what you might see in a ham or a steak.
“Unlike mammals and birds, the thickness of trabecular bone does not increase as the body size of dinosaurs increases. Instead, it increases the density of the appearance of cancellous bone.
“Without this weight-saving adaptation, the skeletal structure needed to support hadrosaurs would be so heavy that the dinosaurs would have had great difficulty moving around.
Dr Fiorillo and his colleagues used technical failure theories and allometric scaling to analyze CT scans of the distal femur and proximal tibia of several dinosaur species: a troodontid, a caenagnathid, a ornithomimide, a therazinosaur and two hadrosaurs (addition of Edmontosaurus and Edmontosaurus regalis).
“Our team is the first to use these tools to better understand the bone structure of extinct species and the first to assess the relationship between bone architecture and movement in dinosaurs,” they said.
The researchers then compared their results to analyzes of extinct and living mammals, such as the Java mouse deer, domestic sheep, Siberian tiger, white rhino, Asian elephant, and Colombian mammoth.
“Understanding the mechanics of dinosaur trabecular architecture can help us better understand the design of other light and dense structures,” said lead author of the study, Dr. Trevor Aguirre, researcher in the Department of Mechanical Engineering. from Colorado State University.
The results were published in the journal PLoS ONE.
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TG Aguirre et al. 2020. Different trabecular bone architecture in dinosaurs and mammals contributes to stiffness and limits bone tension. PLoS ONE 15 (8): e0237042; doi: 10.1371 / journal.pone.0237042
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