Is it past belief that the dinosaurs (or even lions) in PotD will appear in Gyr Abania in some form or fashion? We've seen SE use dungeon monsters like bears and wildebeasts in the past when there wasn't a bear or wildebeast in sight elsewhere, only for them to be plentiful in the Dravanian Forelands and Hinterlands.
It would be rather a questionable use of resources,otherwise, to present these new enemies in such a limited capacity.