plesiosaur

noun

ple·​si·​o·​saur ˈplē-sē-ə-ˌsȯr 

-zē-

: any of an order or suborder (Plesiosauria) of large carnivorous marine reptiles of the Mesozoic with dorsoventrally flattened bodies and limbs modified into flippers

Examples of plesiosaur in a Sentence

Recent Examples on the Web

During the Cretaceous, plesiosaurs grew longer necks and bodies and generally got much longer. —Sara Novak, Discover Magazine, 11 Dec. 2024

This ancient marine environment had produced fossils of plesiosaurs and dolphin-like ichthyosaurs in other locations, so the researchers expected that any new find was going to be something similar. —Jeanne Timmons, Ars Technica, 25 Jan. 2023

Originally thought to be saltwater animals only, recent research indicates that some plesiosaurs could live in freshwater environments (like Loch Ness). —Stephen C. George, Discover Magazine, 23 Jan. 2024

This fearsome creature was not the largest animal of the tropical Cretaceous oceans: It was outclassed by several species of enormous long-necked plesiosaurs, such as the 26-foot-long Callawayasaurus colombiensis. —Santiago Flórez, Smithsonian Magazine, 6 Feb. 2024

Word History

Etymology

ultimately from Greek plēsios close (akin to Greek pelas near) + sauros lizard

First Known Use

1839, in the meaning defined above

Kids Definition

plesiosaur

noun

ple·​sio·​saur

ˈplē-sē-ə-ˌsȯ(ə)r,

-zē-

: any of a group of large Mesozoic marine reptiles with flattened bodies and limbs changed into paddles