After appearing as the Tricic period about 225 million years ago, the pterosaurs took 66 million years ago, until the end of the Cretaceous period, when they died at the same time as the dinosaurs and many other land and sea species. Occupied the air. While many of them corresponded to small animals with wingspan of one meter, some reached impressive dimensions. Is a matter ofAlanqa saharica, A Cretaceous potosaur whose remains were discovered in the Sahara of Morocco. It belongs to the mysterious family of Azhdarchidae, whose ranks consist of animals whose wings can reach 12 meters and which are very elongated cervical vertebrae that give them long necks like giraffes!
Bicycle wheel structure
This very long neck of Azhdarchidae is not without problems for paleontologists. Knowing that, like birds, the bones of these pterosaurs were particularly thin to allow them to lighten their weight and allow them to fly, they long wondered how they could still support the weight of the head . It can actually be more than a meter and a half in length and sometimes pterosaurs caught large prey that had to be carried around in the air.
The answer appears to be from the particular structure of their vertebrae, some of which have been found preserved in three dimensions. One can be examined with a scanner by the team of Carried Williams of the University of Illinois. Initially, the scientist wanted to study the surface of the bone instead of examining it internally. She was actually working on neck mobility and the arrangement of the vertebrae. But the first images reveal some surprising structures at its heart. Surrounding the neural tube, dozens of trabicules (thin bony rods) join the outer part of the spinal disc. They are held in a helix, which gives the vertebrae a “bicycle wheel” in cross section (see picture below).
The internal anatomy of a vertebra with the structure of its bicycle wheel. Credit: Williams et al.
With this astonishing anatomy, Carid Williams called on engineers specializing in biomechanics to understand the role of these bone spacers. His analysis, which is included in an article published in the magazine IScience, Indicated that the trabeculae enhanced the persistence of the vertebrae. Only about fifty can support 90% overweight without breaking the neck. While pterosaurs are sometimes seen as evolutionary dead ends, the study’s authors reveal that their new findings reveal them “Incredibly complex and sophisticated“Extremely light but with strong and durable bones. And there is much to learn from recently discovered fossils, particularly about their ability to fly and their feeding behavior.