Leurospondylus ultimus is a genus of Late Cretaceous plesiosaur from North America. It was discovered and named by Barnum Brown in 1913. It's name is a fusion of two words from the Greek words leuros meaning "even" "flat" or "smooth" and spndylus meaning "vertebra". It's species type is Lultimus which comes from the latin word ultimus meaning "last". Leurosponylus means (smooth even flat vertebra).
The first leurosponylus found was a juvenile and was around 2 meters long as a juvenile. Leurosponylus has the vertebrae of a plesiosaur it also has the scapulae and coracoids similar to a Elasmosauridae. It was found in a brackish environment near the edmonton beds and red deer river. Lerosponylus discovery meant that some species of plesiosaur spent their lives in brackish environments and freshwater while most other plesiosaur lived in saltwater.