The official Japanese Pokémon website has announced that a Pocket Monsters Diamond and Pearl episode featuring Pokémon Ranger Natsuya (ナツヤ) will air on March 18th, 2010. No title has been announced yet but the episode should be DP168. Satoshi and friends must work together to try to capture the legendary Pokémon Heatran. This would mark the first time that Heatran has made an appearance in the main series anime. Heatran made it's anime debut in Arceus - Towards the Continuum of Conquest (アルセウス超克の時空へ).

This episode is separate from the 2 announced special episodes, also announced on the official websites news article. Those episodes will air during Pokémon Sunday.


Source: http://www.pokemon.co.jp/special/ranger3/news/news05.html