Fox has scrapped the planned May preview of new adventure series Terra Nova. In other Fox May scheduling news, American Idol will revert to its original Tuesday-Wednesday air pattern for its finale, to air on Tuesday, May 24 and Wednesday, May 25, the final 2 nights of the season.

Prehistoric drama Terra Nova, from producers Steven Spielberg and Peter Chernin, originally eyed for a midseason premiere this season, had been scheduled to air a two-hour preview in May, followed by a fall launch. Because the producing team needs more time to work on the show’s elaborate visual effects, the preview has been pulled and the series will now premiere in the fall. “Terra Nova is one of the most ambitious television series ever produced,” Fox’s entertainment president Kevin Reilly said. “The cutting-edge visual effects used to create the world of Terra Nova, which is of massive scope and scale, require more time to be realized. This aspect of the series is essential, so we are pushing back the special early preview date to give the visual effects team the time needed for their ground-breaking work.”

The Terra Nova preview was scheduled to air over two nights, Monday May 23 and Tuesday, May 24, at 9 PM. Now Fox will air the season finales of The Chicago Code and Glee in the slots, with Glee following the performance finale of Idol.