It looks like you're going for a steamy tropical theme here, so scouring myths from cultures with similar climates might yield up some nifty races with which to populate your world.
From Aztec mythology, you have the cipactli (caimans dwelling at the center of the earth) and the ahuitzotl (a man-eating water-dwelling dog-monkey with a hand on its tail). The ubiquitous salamander might be a nice touch, as would nagas. And you can always twist around any myths or legends you find to suit your own needs, of course.