Another one of those 1960s sci-fi movies whose poor production standards set your teeth on edge -- but in this case the cast is a hoot!
A space expedition comprised of the prolific John Agar, Wendell Corey ("Cyborg 2087"), Lyle Waggoner ("The Carol Burnette Show"), night club comedian Paul Gilbert (the comic relief), and Stuart Magolin (Angel from "The Rockford Files") lands on an alien world (a studio set), populated by dinosuars (stock-footage lizards) and prehistoric humanoids.
The astronauts provide assistance to two local inhabitants, a man and a woman who serve as a kind of Adam and Eve for this strange world -- which turns out to be Earth! This twist ending was done so often on the Twilight Zone it will never surprise anybody again.
The male humanoid's name is Tang and the female's is Linda ( . . . Linda?). Admittedly the story attempts to interject a few interesting elements; in addition to the roaring lizards, there's a carnivorous plant and a king-sized spider. Remember, I said they TRIED, okay?