Image Credit: Bobby Bank/WireImage.comFanboys who were eager to get a sneak peek of Fox’s midseason drama Terra Nova – the next series from Brannon Braga (24, FlashForward) and David Fury (Lost, Angel) – will have to wait a little longer: 20th Century Fox TV has decided not to unveil the time-traveling drama at Comic Con next week, EW has learned.

Since production on the Jason O’Mara starrer isn’t expected to start until September, the producers don’t have any footage to show the fans in San Diego. Plus, the writers don’t want to reveal too much about the high-concept series, which Fury promises will have an “ongoing mythology.” The action in Terra Nova takes place 100 years in the future and focuses on a family that travels back to the prehistoric era. Steven Spielberg is one of the executive producers.

“There are a lot of surprises, a lot of reveals that come out throughout the course of season,” Fury tells EW. “If we talk about the more interesting aspects of the show now, we’re afraid we’ll ruin the surprise for the audience. In this case, everything is moving along steadily, the script has been well-received. We just don’t have anything to wow anyone with. It’s still in the preliminary stage, It’s a huge undertaking.”

Among the hurdles for the massive project, which has already received a 13-episode commitment from Fox, is nailing down a location. There was some talk about shooting the drama in Australia but the studio is also considering locales in Hawaii and even the mainland. The drama will also feature prehistoric creatures. “There will be dinosaurs that have never been seen before,” promises Fury. “They’ve learned so much since the days of Jurassic Park.”

Adds Braga, “We are presenting a really cool show with a wonderous primeval world. There are not just dinosaurs. There is a whole ecosystem. There will be plenty of adventures and effects, but this is a show about the characters, the humans.”

Casting is still underway for the drama, which is expected to bow in the spring. O’Mara (Life on Mars) will play Jim Shannon, whose family is part of a group of settlers who travel back in time. The show’s auspices read like a who’s who in Hollywood: Besides Braga, Fury and Spielberg, other executive producers include ex-Fox Chairman Peter Chernin, agent-turned-producer Aaron Kaplan, Craig Silverstein (Bones) and Kelly Marcel.