Plesiosaurs

Plesiosaurs, marine reptiles that thrived in the world's seas when dinosaurs ruled the land, swam much like penguins by using their flippers to "fly" underwater, scientists said on Thursday, resolving a debate that began nearly two centuries ago.

Plesiosaurs, marine reptiles that thrived in the world's seas when dinosaurs ruled the land, swam much like penguins by using their flippers to "fly" underwater, scientists said on Thursday, resolving a debate that began nearly two centuries ago.