'When we examined a large sample of plesiosaurs modelled on really well preserved fossils at their real sizes, it turns out that most plesiosaurs had necks below this high-drag threshold, within which neck can get longer or shorter without increasing drag,' said study author Dr Benjamin Moon at Bristol.
This debunks a long-standing idea that there is an optimal body shape for ensuring low drag through the water.īody size is more important than body shape in determining the energy economy of swimming for aquatic animals, the experts say.Īnother key finding was that the large necks of extinct elasmosaurs did add extra drag, but this was compensated by the evolution of large bodies.Īlthough plesiosaurs did experience more drag than ichthyosaurs or whales of equal mass, these differences were relatively minor.
Researchers found that big bodies help overcome the excess drag produced by extreme morphology, such as long necks. 'These experiments are performed on the computer, but they are like water tank experiments.' 'We created various 3D models and performed computer flow simulations of plesiosaurs, ichthyosaurs and cetaceans,' said study author Dr Susana Gutarra Díaz of Bristol's School of Earth Sciences and the National History Museum of London. The plesiosaurs included elasmosaurs, which had the longest necks of the plesiosaurs.Īll the extinct creatures were compared with cetaceans – a modern-day order of aquatic mammals comprising the whales, the dolphins and the porpoises. Plesiosaurs are thought to have appeared in the latest Triassic Period, about 203 million years ago. These included ichthyosaurs, a large group of fish-shaped marine reptiles that first appeared around 250 million years ago and disappeared before the end-Cretaceous extinction (65 million years ago).Īnother extinct tetrapod group looked at was the plesiosaurs, marine reptiles with four flippers and extraordinarily long necks. The study was conducted by researchers at the University of Bristol, who created various 3D models and performed computer flow simulations to study different extinct tetrapods (four-limbed vertebrates), based on evidence from fossils.
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