Pheromosa

Been pouring over the book since I got it. Spending all my time recently on the Pokémon Box, since I thought it might be closest to where I live.

I get it. Lots of forest and water Pokémon sightings, so he was in a forested area with waterways. But the Pheromosa sighting has me confused. It’s found only in the Ultra Desert. How does that fit in with everything else?