Riolu

The fourth-generation (Generation IV) of the Pokémon franchise features 107 fictional creatures introduced in the 2006 Nintendo DS games Pokémon Diamond and Pearl.

The following list details the 107 Pokémon of Generation IV in order of their National Pokédex—an in-game electronic encyclopedia that provides various information on Pokémon—number. The first Pokémon, Turtwig, is number 387 and the last, Arceus, is number 493. Alternate forms that result in type changes and Mega Evolutions are included for convenience.

Shaymin has a second form activated by using a Gracidea flower in the daytime. As opposed to its original Land Forme, Shaymin becomes the Grass/Flying-type Sky Forme. Shaymin's Sky Forme will revert into its Land Forme during the night, while frozen solid, or if it is deposited in the PC. Shaymin was officially revealed in February 2008, when it was listed as a star of Giratina and the Sky Warrior. In early June of the same year, its Sky Forme was revealed.

...
Wikipedia