The discovery that some plesiosaurs could have lived in freshwater has re-ignited the debate on Nessie.
The famous Scottish loch monster is often said to be a plesiosaur - but just how plausible is that?
Dating back 150 million years, this prehistoric reptile is the oldest creature ever found in the region.
Palaeontologists in Russia have discovered a huge new sea creature that lived 130 million years ago.
Palaeontologists have uncovered the remains of a huge prehistoric predatory marine reptile.