Plesiosauria Plesiosauria The Plesiosauria (; Greek: πλησίος, "plesios", meaning "near to" and "sauros", meaning "lizard") or plesiosaurs are an order or clade of Mesozoic marine reptiles (marine Sauropsida), belonging to the Sauropterygia. Plesiosaurs first appeared in the latest Triassic Period, possibly in the Rhaetian stage, about 203 million years ago. They became especially common during the Jurassic Period, thriving until their disappearance due to the Cretaceous–Paleogene extinction event at the end of the Cretaceous Period, about 66 million years ago. They had a worldwide oceanic distribution. Plesiosaurs were among the first fossil reptiles discovered. In the beginning of the nineteenth century,
The Age of Reptiles the mural's beginning to the end of the Cretaceous period, 65 million years ago. Each period's length on the mural is proportional to the period's length in geologic time. Each period of time is divided by large trees in the foreground. Animal species are in bold. Devonian Carboniferous Permian Triassic Jurassic Cretaceous "The Age of Reptiles" won Zallinger several awards. Zallinger was awarded with a Pulitzer Fellowship in Art in 1949, and the painting was featured as a postage stamp in 1970. Despite its somewhat outdated view of dinosaurs, "The Age of Reptiles" is still notable for its historical and