There's a sense in which the dinosaurs of Jurassic World are actually entirely new species, then, different to anything that lived 65 million years ago. The films have always tried to get around these problems as much as possible, hand-waving them away with an element of pseudoscience so, for example, in Jurassic Park scientists filled in gaps in dinosaur DNA with DNA from modern animals, such as frogs, unwittingly introducing an element of asexual reproduction to the creatures. To be fair, this kind of scientific inaccuracy is perfectly understandable these are films, not scientific treatises.