The plesiosaurs are characterized by four uniform fins. Whether they rowed or flew under water could be reconstructed thanks to the combination of paleontological and engineering methods.
Plesiosaurs, which lived around 210 million years ago, have adapted in a unique way to life under water: their front and rear legs have developed into four uniform, wing-like fins in the course of evolution. How they could get on with it in the water, Dr. Anna Krahl worked out in her dissertation supervised at the Ruhr University Bochum and the Rheinische Friedrich-Wilhelms-Universität Bonn. Among other things, by using the finite element method, which is widespread in engineering, it was able to show that the fins had to be twisted in order to advance. Using bones, models and muscle reconstructions, she was able to reconstruct the movement. She reports in the PeerJ journal from 3. June 2022.
Plesiosaurs belong to a group of dinosaurs, the Sauropterygia or paddle lizards, who have adapted to a life in the sea again. They developed in the late Triassic 210 million years ago, lived at the same time as the dinosaurs and died out at the end of the Cretaceous period. Plesiosaurs are characterized by an often extremely elongated neck with a small head - the Elas mosaic animals even have the longest neck of all vertebrates. But there were also large predatory shapes with a rather short neck and huge skulls. In all plesiosaurs, the neck sits on a teardrop-shaped, hydrodynamically well-adapted body with a very shortened tail.