Saurophaganax ("lord of lizard-eaters") is a dubious, chimeric genus of large saurischian dinosaur, possibly a sauropod, from the Late Jurassic (Kimmeridgian) Morrison Formation of Oklahoma, United States.

[4] In 2024, Danison and colleagues revised the referral of various specimens assigned to Saurophaganax maximus including the fragmentary holotype neural arch (OMNH 1123) based on their comparative analysis.

Since the holotype neural arch is so fragmentary, the researchers could not confidently refer it to a theropod or sauropod, so they considered Saurophaganax maximus to be a nomen dubium.

[10] In 2019, Rauhut and colleagues noted that the definitive taxonomic placement of Saurophaganax within Allosauroidea is unstable, being recovered as a sister taxon of Metriacanthosauridae or Allosauria, or even as a basalmost carcharodontosaurian.

The Morrison Basin where dinosaurs lived, stretched from New Mexico to Alberta and Saskatchewan, and was formed when the precursors to the Front Range of the Rocky Mountains started pushing up to the west.

[15] The Morrison Formation records an environment and time dominated by gigantic sauropod dinosaurs such as Barosaurus, Apatosaurus, Brontosaurus, Camarasaurus, Diplodocus, and Brachiosaurus.

[17] Other vertebrates that shared this paleoenvironment included ray-finned fishes, frogs such as Eobatrachus, salamanders, turtles, sphenodonts, lizards, terrestrial and aquatic crocodylomorphs like Goniopholis, and several species of pterosaur like Kepodactylus.