Merrie Melodies - Daffy Duck and the Dinosaur (1939)

Daffy Duck and the Dinosaur is a 1939 Warner Bros. Merrie Melodies animated cartoon short directed by Chuck Jones. The cartoon was released on April 22, 1939, and is the first Daffy Duck cartoon directed by Jones.
Daffy Duck and the Dinosaur is set in a chronologically twisted Stone Age and features Daffy Duck, a caveman named Casper (a caricature of Jack Benny), and his pet Apatosaurus, Fido.
This is the last cartoon with the Vitaphone intro, which was first used in The Phantom Ship in 1936.

Production notes:
Most of Chuck Jones-directed cartoons from this era (such as the ones featuring Sniffles the Mouse) were very heavily inspired by Walt Disney's cartoon shorts, placing more emphasis on story and animation than gags. Daffy Duck and the Dinosaur shows the faintest hints of deviation from such cartoons, which eventually led to the fast-paced Jones cartoons of the 1940s, such as The Dover Boys and The Draft Horse.
This is also an important milestone in the evolution of Daffy Duck's personality. While Tex Avery and Bob Clampett had depicted Daffy as completely insane, irrational, and uncontrollable in their previous cartoons with the character, Jones depicted Daffy here as somewhat more thoughtful and calculating. Jones and Friz Freleng continued to develop Daffy's personality in this direction throughout the 1940s and 1950s.