In `` The Valley of Gwangi '' , Gwangi is billed as an `` Allosaurus '' , although Ray Harryhausen based his model for the creature on Charles R. Knight 's depiction of a `` Tyrannosaurus '' .
Gwangi is billed as an `` Allosaurus '' , though Ray Harryhausen based his model for the creature on Charles R. Knight 's depiction of a `` Tyrannosaurus '' .