Washington (AFP)

Huge flying reptiles, the pterosaurs of the Azhdarchidae family sliced ​​through the skies during the time of the dinosaurs, using their enormous beaks to hunt fish and other animals.

But it's another part of their anatomy that has always intrigued scientists: their neck.

Researchers estimate that the latter could be up to three meters long - more than that of a giraffe - thus raising the mystery of how these animals could support its weight.

Thanks to the analysis of samples of well-preserved vertebrae, from excavations in Morocco, a team of scientists thinks they have the answer.

The key to the riddle seems to lie in a complex assembly of rays inside these vertebrae which, although ultra-light, supported the weight of the pterosaur's head and neck.

Cariad Williams, lead author of the article in the journal iScience, told AFP that before a thorough examination, the research team already suspected that the inside of the animal's spine contained a sophisticated internal structure.

But after analyzing the results of a scan, "we couldn't believe what we had discovered - this is one of the most unique structures we have ever seen," said the doctoral student. from the University of Illinois at Urbana-Champaign, USA.

The structure has no known equivalent in the animal kingdom, modern or extinct, and the researcher said she was "surprised that no one has discovered it before".

- "Tremendously complex" -

The neural tube, which houses the nerves through the spine, is located in the center of the vertebra and connects to the outer walls of the latter via fine bones called trabeculae, arranged in rays and crossing each other. , like a bicycle wheel.

The spokes are also arranged along the length of the vertebra, giving it a helical appearance and adding more strength to the structure.

The team of researchers then worked with biomechanical engineers, whose calculations suggest that with just about 50 of these ray-shaped bones, the weight that pterosaurs could support was increased by 90%.

Co-author of the study, David Martill of the University of Portsmouth in the UK said in a statement that the discovery resolved "many biomechanical questions about how these creatures were able to support their massive heads - long over 1.5 meters - mounted on necks longer than those of the modern giraffe - while retaining the ability to fly ".

Relatively little is known about pterosaurs, which were previously overlooked in scientific studies because they were considered of little interest in evolutionary research.

Yet this finding reveals them as "formidably complex" and worthy of much further study, said David Martill and the research team.

© 2021 AFP