Neusticosaurus (meaning "swimming lizard") is a genus of pachypleurosaurid that lived during the Triassic Period. It was a basal sauropterygian, and had a long neck. The type species is N. edwardsi. Neusticosaurus staubi (formerly known as Pachypleurosaurus) is now considered dubious. It can grow 18 inches long, it was one of the smallest nothosaurs.
Neusticosaurus has never appeared or been mentioned in any Jurassic Park films or books, it has however appeared in Jurassic Park III: Park Builder under its former name Pachypleurosaurus.