Board Thread:General Discussion/@comment-26237273-20150617140442/@comment-13531781-20150717231409

Collector1 wrote: There is no evidence of Stegosaurus on Isla Nublar, so unless there's evidence that says otherwise there were no populations of Stegosaurs before Jurassic World. I'm pretty sure Troodon went extinct at least during the clean up of Jurassic Park or during the construction of Jurassic World.

I like to think that the Parasaurolophus, Triceratops, and Gallimius that live in Jurassic World are descendants of the populations that survive the 1993 Isla Nublar Incident, somewhat like Rexy.

I think Herrerasaurus went extinct in the wild due to competition from Velociraptor and other advanced carnivores. Actually on the maps and embryos, Stegosaurus was on Nublar. The herbivores are probably descendants and the originals, depending on their life spans