Well, in my fevered mind, I quickly put little labels on them based on there names. Hence, Gensia was a fertile-yet-wild land, Handia contained the least "monsters", with the varying lands and peoples not needing some great dragon or another to tell them what to do (as in, focusing on the "hand" part of the name to construct a mildly humanoid-centric place), Inventia being rather advanced as a whole, yet suffering from the actions there mages infliced on the now-potent wildlife (Do not feed the Rhino-Snakes) , and Tremoria being a dry, rocky land, perhapes focusing on reptiles and such. Hence, Rock Munchers feeding on the mineral-rich substances that are churned out by volcanic activity.
As for the position, I would say its that little sliver of land around the eastern rim. Leaves a thought that perhapes the ancesters of the Dinos might have flown over the Rim, which means its not so much as a lost world as a new one that was found by the gigantic airborn reptiles first.