Definition of elasmosaur in US English:


(also elasmosaurus)


  • A Cretaceous plesiosaur with a long neck shaped like that of a swan.

    Family Elasmosauridae, infraorder Plesiosauria: several genera, including Elasmosaurus

    • ‘Elasmosaurus was the longest member of the elasmosaur family and in fact, the longest-known plesiosaur.’
    • ‘Storrs considers this species a synonym of P. guilelmiimperatoris, while Robert Bakker asserts that it is an early elasmosaur, and transfers it to the genus Microcleidus (as M. brachypterygius).’
    • ‘Like the rest of the Plesiosauroidea, elasmosaurs had a barrel-shaped body with four paddle-shaped flippers.’
    • ‘However, all elasmosaurs are quite similar, and extreme, in overall body morphology.’
    • ‘The remains include the bones of dinosaurs, birds, and large marine reptiles such as mosasaurs and elasmosaurs, as well as fossilized sponges, mollusks, pine cones, and diverse fish teeth.’


Late 19th century: from modern Latin Elasmosaurus, from Greek elasmos ‘beaten metal’ + sauros ‘lizard’.