>There are many Grass-type Pokémon—Marowak’s natural enemies—in the Alola region. This makes Alola a harsh environment for Cubone and Marowak. As a result, they live in close union with their partners. It’s said that their great care for their partners allowed them to gain something like a sixth sense and resulted in their changed form.
>allowed THEM

Based on the official description for Alolan Marowak, it seems Cubone has an Alolan form too.
>but the Japanese trailer showed a regular Cubone!
They could be hiding Alolan Cubone from us for now. Or, I'm wrong, and there is no Alolan Cubone.

Thoughts?