Scientists have been trying for decades to understand how pterosaurs, the first vertebrates to conquer the air, evolved from small, agile creatures of the early Mesozoic to majestic giants of the late Cretaceous. This enigma now finds its answer thanks to the discovery of an exceptional fossil.
This fossil is that of Skiphosoura bavaricawhich is simply the missing link between small primitive pterosaurs and their impressive descendants. The results of their excavations were published in the prestigious journal Current Biology.
The little-known story of the masters of the prehistoric sky
The first pterosaurs, appeared around 220 million years agohad very specific characteristics that should not be confused with dinosaurs, a completely different group of reptiles. These flying animals, with a relatively modest wingspan of two meters, had an anatomy adapted to agile flight: a short skull placed on a stocky neck, facilitating opportunistic feeding (without particular preference), and a long tail serving as an aerial rudder.
Their elongated fifth toe allowed them to maneuver the wing membrane, like a lever that allowed them to adjust the power and direction of their movements. Their short wrist bones, in turn, gave them stability in flight, like the hub of a bicycle wheel, which holds the spokes in place and ensures the wheel’s rigidity.
In contrast, their descendants, the pterodactyloids, developed a radically different morphology. These giants, some reaching 10 meters in wingspan, sported massive heads on slender necks, ideally suited for gliding and fishing. Their wrists lengthened considerably, their tails shortened, and their fifth toes gradually became smaller. These anatomical modifications allowed them to become the most efficient aerial predators of their time.
Skiphosoura, the missing link
The discovery of Skiphosoura bavarica completely disrupts our vision of this evolution. This specimen presents a fascinating mix of ancient and modern featurestestifying that a transitional phase has indeed taken place. Its head and neck are already reminiscent of evolved pterodactyloids, suggesting an early adaptation to new hunting strategies. However, its wrists, toes and tail occupy an intermediate position: neither as primitive as its ancestors, nor as specialized as its descendants.
The most remarkable feature of Skiphosoura resides in its short tail, rigid and pointed. This unique characteristic distinguishes it from both earlier and later species, and reveals a previously unknown evolutionary step in adaptation to flight. This configuration suggests that pterosaurs first modified their cranial anatomy before transforming the rest of their bodies.
A complete reconstruction of the evolutionary tree
This discovery is part of a rwider network of recent finds. The recently discovered Scottish fossil Dearc represents another essential link in the evolutionary history of pterosaurs. Older than Skiphosourait illustrates the first anatomical modifications of these flying reptiles. Between these two species are placed the Darwinoptera (a nice tribute to Charles Darwin), an intermediate group which testifies to the progressive transformations of the skull and neck, thus prefiguring these later adaptations.
This sequence of fossils allows paleontologists to reconstruct, step by step, the transformation of pterosaurs over more than 150 million years. “ This discovery is extraordinary », underlines David Hone of Queen Mary University of London. “ It really helps us piece together how these incredible flying animals lived and evolved. We hope that this study will serve as a basis for further work in the future on this important evolutionary transition. “.
Skiphosoura thus represents a central piece in the puzzle of pterosaur evolution. The fossils now tell a continuous story: first the small, agile species hunting in Triassic forests, then the Darwinoptera developing their first long necks, followed by Skiphosoura with its hybrid anatomy, to the gigantic pterodactyloids soaring above the oceans Cretaceous. With each discovery, we understand much better how these reptiles have adapted to new hunting territories.
- The discovery of Skiphosoura bavarica reveals the missing link between primitive pterosaurs and their gigantic descendants.
- This fossil shows a unique evolutionary transition, with intermediate traits mixing old and new adaptations.
- Thanks to key discoveries like that of Skiphosourapaleontologists are able to better reconstruct the evolution of pterosaurs.
