Other mistake: When the velociraptor jumps for Ian, it hits an electric panel and shorts it out (the red lights go off). In the aerial shot of Kelly's acrobatics the panel lights are on and the raptor is gone. When it jumps from the ground to the catwalk the lights are off again. Then on again when Ian and Kelly run from the shed. (01:36:00 - 01:36:48)
Continuity mistake: When Sarah looks up at her jacket, the bag of snacks is on the opposite side of Kelly. The bag is closed and the chocolate bars are unopened. Also, there are no crumbs between the two characters. But as the T-Rex is approaching, Sarah is gathering the now opened snacks and dusting crumbs off the top of their sleeping bag that was not there in the overhead shot. (01:21:29)
Continuity mistake: As the camera pans from Ian to the tent, Sarah, the lantern is out and the front flaps are open/tied back. From the interior shots, that lantern is still lit and the flaps are hanging loose. (01:21:39 - 01:22:07)
Answer: The dinosaurs on Isla Nublar are not mentioned. In the first book they are destroyed by bombing, which makes the second island more surprising - a lost world.