In the Jurassic Park Series the Mountains are located in the inland of Costa Rica. In the first novel a group of Dinosaurs that escaped from either Isla Nublar or Isla Sorna, start to roam free in the jungles of these Mountains.
The dinosaurs species are unknown, however since all dinosaurs that reached the mainland in the novels were carried unseen by boats, it's unlikely that large creatures reached these mountains and since the animals supposedly ate the chickens of local farmers the suspected creatures would have to be carnivorous. Possible species are Procompsognathus, Dilophosaurus or Velociraptor mongoliensis. But some have been mention to be eating lysine rich plants so there might be herbivores like Hypsilophodontid, Othnielia, and Microceratops. Eventually however, these dinosaurs were searched out and destroyed by the Costa Rican government to further cover up the resurrection of the dinosaurs by InGen 
- Crichton, Michael. 1995. "The Lost World". page 27-28.