ARK developers Studio Wildcard took to forum to enlightened PS4 players about the state of things. First of all, as you may already know ARK: Survival of the Fittest is no longer going to be a standalone free-to-play game, instead it is being absorbed back into the main game where Studio Wildcard are currently working to include mod support and iterating quickl on the PC version. When this mode will hit the Xbox One version is currently unknown. As for the main game hitting PS4, Studio Wildcard had some bad news.
"As for the PS4 Release of ARK: Survival Evolved, it is currently up to Sony. We've been informed that we can't release the game on this platform until it has been finished. We would like nothing more than to make ARK available on PS4 as soon as possible, as we already have an awesome PS4 version of the game running internally. If you would like to see it sooner, please let Sony know, as it's unfortunately not our decision."
The game is currently still on track for full release this holiday season, but given the recent changes with Survival of the Fittest being brought back into the main game, that date may have changed. You can currently enjoy the work-in-progress version of ARK: Survival Evolved via Steam Early Access and Xbox Game Preview.