How did Plesiosaurs Swim?

Plesiosaurs are marine reptiles, not dinosaurs and they roamed the seas for much of the Mesozoic.  Fossils of these long-necked, round bodied reptiles have been found in many parts of the world.  The geological record of plesiosaur fossils spans some 135 million years.  However, palaeontologists have debated, almost since the time of Mary Anning, how these carnivorous animals actually moved through water.  It turns out that these animals, some of which were as long as a school bus, actually “flew” through the water, swimming with their front paddles, in virtually the same way that penguins do today.

Studying How Plesiosaurs Moved through Water

A mounted fossil exhibit of a plesiosaur.

A mounted fossil exhibit of a plesiosaur.

With the help and support of plesiosaur fossil expert Dr. Adam Smith (Nottingham Natural History Museum, Wollaton Hall), a team of researchers from the School of Interactive Computing  at the Georgia Institute of Technology, Atlanta, Georgia, United States) recreated the swimming motions of a three metre long, Early Jurassic plesiosaur, whose fossils come from Germany, (Meyerasaurus victor).  A three dimensional computer model of the marine reptile was created and then various swimming modes were tested.  The most efficient locomotion was achieved when just the front flippers were used.  It seems that the rear limbs did little in the way of helping to create forward thrust and momentum.  Instead, they were probably used for steering and keeping stable in the water column.

Commenting on the research, Dr. Smith stated:

“Plesiosaur swimming has remained a mystery for almost 200 years, so it was exciting to see the plesiosaur come alive on the computer screen.  Our results show that the front limbs provide the powerhouse for plesiosaur propulsion while the hind limbs are more passive”.