Jurassic Park Wiki

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. edwardsiNeusticosaurus staubi (formerly known as Pachypleurosaurus) is now considered dubious. It can grow 18 inches long, it was one of the smallest nothosaurs.

Wikipedia has a more detailed and comprehensive article on Neusticosaurus

Jurassic Park

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.