I'm sure there are other continents, though I am surprised just how small these regions are. Put together Kanto and Johto would fit at least three times into my home country. The way the new species show up is...well, interesting, but normally you'd need way, way more that we have around to make for an actually balanced ecosystem.

...I think. I didn't study ecology all that much, but I know there's way more species of animals back home.