A lot of new characters and concepts where revealed in Goseiger Episode 17. GoseiKnight makes his first appearance. He's not what I was expecting from a 6th Ranger, but he seems very cool and should be a good addition to the team. But for right now he remains very mysterious. He even is able to transform into his own Header. The new villains, the Yuumajuu are based off of horror monster movies.
Here are the new profiles for GoseiKnight and the new villains, and below the other new screen shots. It looks like Eri and Moune have gotten new haircuts.
You can find this image added here: GoseiPink Profile
You can find this image added here: GoseiYellow Profile
You can find this image added here: Goseiger Robots
This image is labeled as coming from www.modxtoy.com
New Villains, Yuumajuu
You can find this image added here: Goseiger Group Images
You can find these images added here: Goseiger Monsters