The Son of Suns
A returning motif in Lucas's films, found throughout his student films as well as in THX 1138 and Star Wars, is that of the sun.
Riders astride giant lizards might not have been an entirely novel concept by the mid 70s, but Ron Cobb's take on it had an air of the fantastic, while being grounded in reality. Cobb would go on to work on creatures for Star Wars , and this early design probably inspired the Dewback.