Dinosaurs and the evolution of breathing through bones
- They’re already present from approximately 145 to 66 million years ago within Cretaceous theropods (bipedal dinosaurs that were either carnivorous or herbivorous), pterosaurs (flying reptiles), and sauropods (gigantic long-necked dinosaurs).Thus, to find their origin, the team looked further back to the Triassic (about 252 to 201 million years ago).
- It was so successful that it was maintained by three different groups of extinct species and continues to exist today in the living descendants of dinosaurs.Because lungs don’t usually survive fossilization, one might wonder how scientists are able to ascertain anything about the breathing capabilities of extinct species.
- “Since the earliest dinosaurs didn’t have the invasive pneumatic structure,” she said, “[the air sacs] had to have evolved after that.
- Known as postcranial skeletal pneumaticity, it’s part of an extraordinarily efficient system that rapidly gets oxygen into the blood and extracts heat from the body.Today, that invasive air-sac system is known only in birds.
- And if it evolved after that, logically, pterosaurs had to have evolved it in a parallel way.”In other words, these results suggest that three lineages of extinct species evolved the same respiratory system independently.
- Not so if you have an invasive air sac system.When did these air sacs evolve?
Enlarge/ It takes careful study and the right kind of bones to determine how something like this breathed.8 with Somewhere in Earths past, some branches on the tree of life adopted a body plan th [+10234 chars]