[The Conversation Africa] Sixty six million years ago, sea monsters really existed. They were mosasaurs, huge marine lizards that lived at the same time as the last dinosaurs. Growing up to 12 metres long, mosasaurs looked like a Komodo dragon with flippers and a shark-like tail. They were also wildly diverse, evolving dozens of species that filled different niches. Some ate fish and squid, some ate shellfish or ammonites.