The Unidentified crested hadrosaur was an unknown species of hadrosaur that briefly appeared in the comic Return to Jurassic Park VI.
It has been popularly suggested by the Jurassic Encyclopedia (originally held on the now defunct fansite Jurassic Park Legacy) that this is possibly Lamebosaurs lambei. However, the crest of these hadrosaurs is in a half-moon shape, very different from the crest shape of the actual Lambeosaurus.
At least three of these hadrosaurs were created by InGen for the planed theme park on Isla Nublar. Three of them were briefly seen running around in a paddock when the storm that began the incident began to strike.
It is unknown what happened to these hadrosaurs, but it is likely that they were freed and continued to live on Isla Nublar.