One of the more intriguing marine reptiles that existed during the reign of the dinosaurs would be Nothosaurs. Nothosaurs lived during the Triassic Period, which was when the dinosaurs first evolved. They were ancient relatives of Plesiosaurs, which were among the more famous marine reptiles. I have been intrigued by Nothosaurs because they look like a reptilian mixture between a seal and a mermaid. They are graceful when they swim yet deadly when they need to be. I will be featuring a marine reptile in my dinosaur series that is physically similar to Nothosaurs, but it will be a completely different creature altogether.