Open Paleo

Saurophaganax

Chure, 1995 SAWR-o-FAG-a-naks Disputed

From Greek 'sauros' meaning 'lizard', 'phagein' meaning 'to eat', and 'anax' meaning 'ruler' or 'lord'; meaning 'lord of lizard-eaters.'

154.8–143.1 million years ago Kimmeridgian–Tithonian, Late Jurassic
Late Jurassic stages

Saurophaganax is a dubious, chimeric genus of large saurischian dinosaur, possibly a sauropod, from the Late Jurassic (Kimmeridgian) Morrison Formation of Oklahoma, United States. This taxon was historically considered to represent a species of Allosaurus or very large allosaurid. However, re-examinations of the attributed specimens suggested that it is a chimera of multiple dinosaur genera, since some specimens most likely belong to a diplodocid sauropod, while the other referred specimens could be reassigned to a novel species of Allosaurus.

Under dispute

Saurophaganax maximus has historically been treated as a giant allosaurid, either a distinct genus or a species of Allosaurus (A. maximus; Smith, 1998). Danison and colleagues (2024) argued that the referred material is a chimera of a large Allosaurus and a diplodocid sauropod and that the holotype neural arch is undiagnostic, rendering Saurophaganax a nomen dubium; they erected Allosaurus anax for the theropod material. Pending broad acceptance of that reassessment — and following its retention as a valid taxon in the Tetanurae analysis of Carrano and colleagues (2012) — the genus is kept conservatively at Allosauridae.

Diagnosis

  1. Horizontal lamina along base of each side of neural spine, arising from spine base cranially but free caudally
  2. Atlas lacks prezygapophyses for proatlas and does not roof over neural canal
  3. Chevrons craniocaudally expanded distally

Species

Saurophaganax maximus Chure, 1995 Disputed

Type species

From Latin 'maximus' meaning 'the largest' or 'greatest', reflecting the exceptional size of this large allosaurid theropod.

Holotype
OMNH 1123 , Oklahoma Museum of Natural History
Material
Mid-dorsal neural arch with horizontal lamina along neural spine base
Horizon
Kenton Member, Morrison Formation, Kimmeridgian–Tithonian, Late Jurassic , 154.8–143.1 million years ago
Locality
Quarry 1, east of Kenton, Cimarron County, Oklahoma, United States

Synonyms of the genus

Name Type Reason
Saurophagus preoccupied Name preoccupied by Saurophagus (Aves).

References

  1. Chure, D. J. (1995). A reassessment of the gigantic theropod Saurophagus maximus from the Morrison Formation (Upper Jurassic) of Oklahoma, USA. Sixth Symposium on Mesozoic Terrestrial Ecosystems and Biota, Short Papers (Sun, A.; Wang, Y., eds.) 103-106. China Ocean Press, Beijing. chure1995a
  2. Carrano, M. T.; Benson, R. B. J.; Sampson, S. D. (2012). The phylogeny of Tetanurae (Dinosauria: Theropoda). Journal of Systematic Palaeontology 10(2): 211-300. Informa UK Limited. doi:10.1080/14772019.2011.630927

    Retained Saurophaganax as a valid taxon in a phylogenetic analysis of Tetanurae.

    carrano2012a
  3. Danison, A. D.; Wedel, M. J.; Barta, D. E.; Woodward, H. N.; Flora, H. M.; Lee, A. H.; Snively, E. (2024). Chimerism of specimens referred to Saurophaganax maximus reveals a new species of Allosaurus (Dinosauria, Theropoda). Vertebrate Anatomy Morphology Palaeontology 12(1): 81-114. doi:10.18435/vamp29404

    Reassessed the referred material as a chimera; treated Saurophaganax maximus as a nomen dubium (undiagnostic holotype) and erected Allosaurus anax for the theropod material.

    danison2024a
  4. Molina-Pérez, R.; Larramendi, A. (2019). Dinosaur Facts and Figures: The Theropods and Other Dinosauriformes. Princeton University Press.

    Source of the mass and hip height estimates.

    molina-pérez2019a
  5. Smith, D. K. (1998). A morphometric analysis of Allosaurus. Journal of Vertebrate Paleontology 18(1): 126-142. Informa UK Limited. doi:10.1080/02724634.1998.10011039

    Treated the Saurophaganax material as Allosaurus (Saurophaganax) maximus in a morphometric study.

    smith1998a