A team of paleontologists and mechanical and biomedical engineers compared CT scans of fossil bones of hadrosaurs and other dinosaurs with bones of extinct and living mammals and found that the dinosaur’s tracheal bone architecture could uniquely support large weights (up to 47,000 kg) and other than that of mammals and birds.
Life reconstruction of Kamuysaurus japonicus, a species of hadrosauride (duck-billed) dinosaur that lived about 72 million years ago (Cretaceous) in what is now Japan. Image Credit: Kobayashi and others, doi: 10.1038 / s41598-019-48607-1.
The largest terrestrial dinosaurs were enormous creatures whose body mass placed massive gravitational loads on their skeletons.
Previous studies examined dinosaur bone strength and biomechanics, but the relationships between their trabecular bone architecture and mechanical behavior have not been studied to date.
“The structure of the trabecula, like spongy bone that forms in the interior of bones we study, is unique in dinosaurs,” said study co-author Dr. Tony Fiorillo, a paleontologist in the Huffington Department of Earth Sciences at Southern Methodist University.
“The trabecular bone tissue surrounds the small spaces like holes in the interior part of the bone, like what you might see in a ham or steak bone.”
“Unlike mammals and birds, the trabecular bone does not increase in thickness as the body size of dinosaurs increases. Instead, it increases in density from the appearance of spongy bones. ”
“Without this weight-saving adjustment, the skeletal structure needed to support the hadrosaurs would be so heavy, the dinosaurs would have a hard time moving.”
Dr. Fiorillo and colleagues used theories of technical failure and scale of allometry to analyze CT scans of the distal femur and proximal tibia of various dinosaur species: a trodontide, a caenagnathid, an ornithomimide, a therizinosaur, and two hadrosaurs (Edmontosaurus annectens en Edmontosaurus regalis).
“Our team is the first to use this tool 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 findings with scans of extinct and living mammals, such as the Java mouse heart, the domestic sheep, the Siberian tiger, the white rhinoceros, the Asian elephant and the Colombian mammoth.
“Understanding the mechanics of the trabecular architecture of dinosaurs can help us better understand the design of other lightweights and dense structures,” said student author Dr. Trevor Aguirre, a researcher in the Mechanical Engineering Department at the Colorado State University.
The findings were published in the journal PLOS ONE.
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TG Aguirre and others. 2020. Different trabecular bone architecture in dinosaurs and mammals contribute to stiffness and boundaries of bone stem. PLOS ONE 15 (8): e0237042; doi: 10.1371 / journal.pone.0237042
