Niantic is skipping a a few Pokemon generations in the coming weeks. Pokemon Go will be introducing the Alolan forms of Generation 1 Pokemon; jumping straight to Pokemon first seen in the seventh generation of games.
Pokemon Sun and Moon were the first to introduce the idea of existing Pokemon with alternate types. Allowing the series to expand the number of existing Pokemon without directly affecting the Pokedex numbering. In all, there are 18 Alolan forms to be introduced.
Among these are the new Grass-Dragon type Exeggutor, Ice-Fairy type Ninetales, and Electric-Psychic type Raichu. It’s entirely unclear how these new types will evolve, seeing that the base form of some of the Pokemon are unchanged.
Niantic hasn’t revealed when it will be releasing these new Pokemon, but the announcement says that they will be appearing in the coming weeks.
[Source: Pokemon Go Live]