Swimming paddle of a Pliosaur found in Kimmeridgian sediment, dating 155 million years ago in Dorset, UK. Pliosaurs were marine reptiles that lived during the Late Jurassic. Like plesiosaurs, Pliosaurs had 4 limbs of equal power which they used in the manner of underwater flight unique in the animal kingdom. Since all 4 limbs have similar sizes and characteristics, it is unclear whether this paddle is a forelimb or a hindlimb. Collection Jean-Philippe et Francois-Xavier Blouet, paleontologists.