Temporal range: Late Jurassic
An artist's illustration of Saurophaganax maximus by Sergestus
Scientific classification
Kingdom: Animalia
Phylum: Chordata
Class: Sauropsida
Clade: Dinosauria
Order: Saurischia
Suborder: Theropoda
Family: Allosauridae
Genus: Saurophaganax
Chure, 1995
Species: S. maximus
Type species
Saurophaganax maximus
Chure, 1995

Saurophaganax (Greek meaning "lord of lizard eaters") is a genus of allosaurid theropod from the Morrison formation, from late-Jurassic Oklahoma (late Kimmeridgian age, about 151 million years ago). Some paleontologists consider it to be a species of Allosaurus (A. maximus). Saurophaganax represents a very large Morrison Allosaurid characterized by horizontal laminae at the bases of the dorsal neural spines above the transverse processes, and "meat-chopper" chevrons.

Saurophaganax is one of the largest known theropods of the entire Jurassic period, it weighed 4.5-8.3 tonnes, with a length of 10 to 12.9 meters, making it larger than Allosaurus and Torvosaurus.

In 1931 and 1932 John Willis Stovall uncovered remains of a large theropod near Kenton in Cimarron County, Oklahoma in layers of the late Kimmeridgian. In 1941 these were named Saurophagus maximus by Stovall in an article by journalist Grace Ernestine Ray. The generic name is derived from Greek sauros, "lizard" and phagein, "to eat", with the compound meaning of "eater of saurians". The specific epithet means "the largest" in Latin. As the naming article did not contain a description., the name remained a nomen nudum. In 1950 Stovall described the finds.

However, in 1987 Spencer George Lucas e.a. concluded a lectotype had to be designated among the many bones: OMNH 4666, a tibia. Later it was discovered that the name Saurophagus was preoccupied: it had already in 1831 been given by William Swainson to a tyrant-flycatcher, a real eater of lizards. In 1995 Daniel Chure named a new genus: Saurophaganax, adding Greek anax, "ruler", to the earlier name. Chure also established that the lectotype tibia was not diagnostic in relation to Allosaurus. He designated another element as the type specimen: OMNH 01123, a neural arch.

This was not intended as a neotype of the old genus but as the holotype of a genus different from "Saurophagus". The type species Saurophaganax maximus, based on diagnostic material, is thus not to be considered conspecific with Saurophagus maximus based on a undiagnostic bone — which species Chure later stated to be a nomen dubium — and Saurophaganax is not a renaming of "Saurophagus". Much of the material previously referred to Saurophagus maximus, namely those diagnostic elements that could be distinguished from Allosaurus, were by Chure referred to Saurophaganax maximus.

They contain disarticulated bones of at least four individuals. Saurophaganax is in the official state fossil of Oklahoma, and a large skeleton of Saurophaganax can be seen in the Jurassic hall in the Sam Noble Oklahoma Museum of Natural History.

Though being officially classified as Allosaurid, Saurophaganax seems to have more carcharodontosaurid-like laminae on it's vertebra. This makes the position of this genus even more confusing than it already is. More research and analysis on Saurophaganax material is definitely required.


Skeletal reconstruction of Saurophaganax by Lamborlobator. This reconstruction includes undescribed material and is subject to potential future updates.

According to the Sam Noble Oklahoma Museum of Natural History vertebrate paleontology collection, there are over 200 undescribed elements of Saurophaganax.

Disputed validity[]

The identification of Saurophaganax is a matter of dispute. It has been described as its own genus, or as a species of Allosaurus - Allosaurus maximus. New possible Saurophaganax material from New Mexico may clear up the status of the genus. However, the most recently conducted research establishes Saurophaganax as a different taxon, due to distinctions in the anatomy of the vertebrae.

Saurophaganax was probably more robust than Allosaurus.


Saurophaganax as depicted in the BBC TV show Planet Dinosaurs.



Saurophaganax was the largest known apex predator of the Morrison formation. It could have hunted and scavenged on anything available in it's area. Saurophaganax was able to hunt any dinosaur from Amphicoelias; in packs; to Camptosaurus. It's diet probably included large sauropods such as Amphicoelias, Diplodocus and Apatosaurus. It's unknown if it hunted alone or hunted in groups or packs when hunting large sauropods akin to other allosaurid and Carcharodontosaurid species.


Th - Skeleton of Saurophaganax

Mounted Saurophaganax specimen.

Saurophaganax was one of the largest carnivore species of Late Jurassic North America. Ray even gave an estimate of the body length of fifteen metres and Chure of fourteen, although this estimate is outdated, and newer estimates put it at 11-12.9 meters in length. The fossils known of Saurophaganax (both the possible New Mexican material and the Oklahoma material) are known from the one of the earliest parts (Kenton member) of the Morrison formation, suggesting that they were either always uncommon or appeared rather early in the fossil record. Although sharing the same formation with other large theropods, such as Torvosaurus and Allosaurus, the stratisgraphy of Saurophaganax suggests that it never met them, as both Torvosaurus and Allosaurus have never been found in the Kenton member. This animal lived in a harsh arid environment with potential peak temperatures of 50 degrees celcius. Being rarer than its contemporaries, making up one percent or less of the Morrison theropod fauna, not much about its behavior is known. Stovall in Oklahoma also unearthed a considerable number of Apatosaurus specimens, a possible prey for a large theropod.

In popular culture[]

  • Saurophaganax appeared in a few episodes of the anime show Dinosaur King. Including the 2nd Season.
  • It also appeared in its first dinosaur documentary in the fourth episode of Planet Dinosaur, where one stole a carcass of a Camptosaurus from an Allosaurus who hunted it.
  • It appears as an alternative species skin for the Allosaurus in Prehistoric Kingdom.
  • It also appears in the remake of the ROBLOX game Era of Terror, though it’s incorrectly called allosaurus.
  • a group of S. maximus are characters in the webcomic Morrison by Wyatt Andrews. They are referred to as “Titan Allosaurs”

Other Wikis[]