Plesiosaur
Timeline: Jurassic through Cretaceous Period
Is a carnivorous aquatic reptile with a broad body and a short tail. Retaining their ancestral two pairs of limbs, which evolved into large flippers. They were slow swimmers. The name applies to the true plesiosaurs (Plesiosauroidea) which include long-necked (elasmosaurs) and short neck (polycotylid) forms that belong to the larger taxonomic rank of Plesiosauria. Pliosaurs were the short-necked, large-headed plesiosaurians that were the apex predators for much of the Mesozoic. The term comes from the Greek “plesios” meaning “near or close to” and “sauros” meaning “lizard”. When they were first discovered it was described as a “snake threaded through the shell of a turtle” (even though there is no shell). First discovered in England by Mary Anning (early 1800s). Were the first fossil vertebrates to be described by science. Surviving from Jurassic until the K-T extinction at the end of the Cretaceous Period. Even though they are Mesozoic reptiles, living during the time of the dinosaurs, they were not dinosaurs. Plesiosaurs evolved from earlier, similar forms such as pistosaurs or very early, longer-necked pliosaurs. There are a number of families of plesiosaurs, which retain the same general appearance and are distinguished by various specific details.
fossil at National Museum of Natural History
Smithsonian, National Mall, Washington, D.C.
Bibliography/ More Information:
Paleo database
Plesiosaur website:
Wikipedia: plesiosaur
