Arkane Studios has posted on their website that they are collaboration with 2K Marin on Bioshock 2.

"Arkane Studios is pleased to announce its collaboration with 2K Marin and contributions to Bioshock 2 in the areas of design, animation and art. We’re excited about this game, which underscores Arkane Studios’ core values."

With Arkane’s addition to Bioshock 2’s development, it ups the count to four developers. Digital Extreme is working on the multiplayer, and 2K Australia is helping in co-developing the game with 2K Marin.

Bioshock 2 is scheduled to be released this fall on the PS 3, Xbox 360 and PC.