A new illustration of one dinosaur exhalation of an inflated cloud may appear as if the animal is steaming. But in reality, the artwork simply depicts a dinosaur breathing on a cold morning. And it turns out that this dino breathed in a way unlike any seen in this group of dinosaurs before.
Scientists found unusual ribs and sternum in an unusually well-preserved fossil skeleton Heterodontosaurus tucki, a turkey-sized dinosaur, plant-eating ornithic or bird-hippie – the group that includes dinosaurs with duck foxes, stuffed dinosaurs like Triceratops and armored dinosaurs like Ankylosaurus.
X-rays of the fossil, discovered in the Eastern Cape of South Africa in 2009, enabled scientists to digitally reconstruct the skeleton in 3D. Their models revealed skeletal features previously unknown to ornithologists that showed ribs and hip bones connected to muscles to help the animal breathe in a way that was new to dinosaurs: through breast and abdominal enlargement.
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H. tucki measured about 1
Because H. tucki the skeleton was almost complete, paleontologists discovered a group of small, slender abdominal ribs called gastralia. These ribs are found in crocodiles and other modern reptiles and play a role in respiration but were previously unknown in ornithonic dinosaurs, said lead study author Viktor Radermacher, a doctoral student at the Department of Earth and Environmental Sciences at the University of Minnesota at Minneapolis.
“Gastralia were considered absent from all bird organizations, but we show that they have retained them for a very short period of their early development,” Radermacher told WordsSideKick.com in an email. H. tucki also had paddle-shaped ribs and elongated sternum plates that could move with the ribs attached to the sternum to facilitate breathing. Such features “are lost in later ornithic,” Radermacher said. This tells us that early members of this group “did something very different with their bodies,” he added.
Mammals breathe by expanding and contracting their lungs using an organ called a membrane that pushes air in and out. Birds – a modern lineage of teropod dinosaurs – use another method in which a network of air sacs distributes oxygen by running it in a loop through the birds’ lungs and bodies. Paleontologists who previously reconstructed the inner anatomy of extinct dinosaurs found evidence of similar air sacs, suggesting that most dinosaurs breathed like modern birds, Reported WordsSideKick.com in 2005.
But H. tucki‘s anatomy suggested that this dinosaur had a different strategy. By bending muscles connecting the gastralia and pelvis, and sternal plates and bone shovels, the dinosaur would have inhaled air by blowing its stomach and chest and then relaxing those muscles to push air out, according to the new study.
This type of breathing is similar to the respiration of certain reptiles; crocodiles breathe using their chests, stomachs, “and really weird muscles” in their bodies, while lizards breathe by expanding and contracting their entire bodies “and even the neck,” Radermacher said. Pterosaurs, which are flying reptile cousins of dinosaurs, have some bony breast properties similar to those of H. tucki, suggests that pterosaurs may also have breathed with their chests and stomachs, he added. (Pterosaurs, crocodiles and dinosaurs all belong to the arkosaur group).
Prior to this discovery, some scientists suspected that ornithic might have breathed differently than other dinosaurs; this well preserved H. tucki copy “was the missing piece of the puzzle” to confirm this hypothesis, Radermacher said.
Originally published on WordsSideKick.com.