Plesiosaurs

Plesiosaurs were among the largest aquatic animals of their time, ranging in size from 6 feet to over 50 feet long. Plesiosaurs all possess a short tail, broad body and four flippers. Sometimes referred to as dinosaurs, these monsters of the deep were actually reptiles. They first appeared in the Late Triassic Period, and were found in every ocean by the end of the Cretaceous. This group of reptiles is made up of two major types, the long-necked plesiosaur, and the short-necked long-skulled pliosaur. The long necked plesiosaur was built for mobility and may have preferred shallow waters. The short-necked pliosaur may have been fast swimmers preferring the open seas.