Director: George Pal
Cinematography : Harold E. Wellman
Art Direction : George W. Davis / William Ferrari
Makeup Department: William Tuttle
Special photographic Effects: A. Arnold Gillespie /Robert R. Hoag
Matte painting supervisor:Lee LeBlanc
Matte artist: Matthew Yuricich
Visual effects (animation) Project unlimited: Wah Chang / Jim Danforth/ Gene Warren
Matte paintings made at MGM matte department under Lee LeBlanc.
That was a reused matte painting of the Roman circus painted by Peter Ellenshaw for Quo Vadis? (1951) It was also a MGM film, so they just add the triangle hole painting on the floor.
Miniatures made by Arnold Gillespie unit.
Mutant creature makeup by William Tutle.