This is the supercontinent that is Synsolic. Place names are written in their Solan versions where they have them, and as loanwords from their languages of origin where they don't. For more information on any given locale, see Environments.
The 'Humanoid Ranges' map shows which areas have been historically occupied by a single species. This does not mean there was no intermixing of species- in fact, quite the opposite. The ranges shown are an average. Neither do they represent borders- some borders existed within city-states or territories, but they were much smaller-scale, and changed often enough that the purposes of mapping them are minimal. These ranges exist solely to show what broad areas of the continent people occupied- what coastlines they lived on, what biomes they adapted to- how they came to be who they are today. The mapped ranges cease as much utility after the cataclysm- all species generally shifted away from the north and their occupied regions merged and shrunk dramatically.
Nightlings are not mapped because their presence on the surface is relatively new, evolutionarily speaking. Their distribution is marked not by historical presence on the land but by migration from the caverns as means of safekeeping.
Various species of merfolk generally do not experience much overlapping of habitat. Chimerae are kept seperate from surface merfolk by the pressure they are adapted to, and iarans and nix are kept apart by the drastic temperature difference of the northern and southern waters- though the two do live together often in mid-latitude seas.