Open Paleo

Cryolophosaurus

Hammer & Hickerson, 1994 KRY-uh-LOH-fuh-SAWR-uhs /ˌkraɪəˌloʊfəˈsɔːrəs/

From Greek kryos, 'cold/icy/frozen', + Greek lophos, 'crest', + Greek sauros, 'lizard'; means 'frozen-crested lizard', referring to its discovery in Antarctica and its distinctive head crest

199.5–184.2 million years ago Sinemurian–Pliensbachian, Early Jurassic
Early Jurassic stages

Cryolophosaurus is a genus of large theropod dinosaur known from only a single species, Cryolophosaurus ellioti, from the Early Jurassic of Antarctica. It was one of the largest theropods of the Early Jurassic, with the subadult, being estimated to have reached 6-7 meters (20-23 ft) long and weighed 350-465 kilograms (772-1,025 lb).

Under dispute

Cryolophosaurus ellioti was described with possible ceratosaurian, tetanuran or abelisaurian affinities (Hammer and Hickerson, 1994) and has been recovered as the earliest stem tetanuran (Carrano and colleagues, 2012), but most analyses place it outside Averostra and Tetanurae as a non-averostran neotheropod in a grade with Dilophosaurus and Zupaysaurus (Smith and colleagues, 2007; Nesbitt and colleagues, 2009; Marsh and Rowe, 2020). It is placed conservatively at Neotheropoda incertae sedis.

Diagnosis

  1. Nasals extend posteriorly as high ridges that join with a large furrowed lacrimal crest
  2. Frontal crest runs approximately perpendicular to the length of the skull and curves anteriorly as it rises, with furrowed surface bearing small vertical projections along the dorsal surface
  3. Orbital horn fused to the crest on each side
  4. Jugal crosses the lower lateral temporal opening and sutures with the squamosal, splitting the opening into two parts
  5. Pneumatic lacrimal present but lacks the large lacrimal opening typical of larger carnosaurian tetanurans

Species

Cryolophosaurus ellioti Hammer & Hickerson, 1994

Type species

Named for geologist David Elliot, who made the initial discovery of the fossils on Mount Kirkpatrick in Antarctica.

Holotype
FMNH PR1821 , Field Museum of Natural History
Material
Partial skull with articulated mandibles, femur, ilium, ischium, pubis, tibiotarsus, fibula, and two articulated metatarsals; skull approximately 65 cm long
Horizon
lower Hanson Formation, Sinemurian–Pliensbachian, Early Jurassic , 199.5–184.2 million years ago
Locality
Mt. Kirkpatrick, Beardmore Glacier, Antarctica

Synonyms of the genus

Name Type Reason
Elvisaurus nomen nudum Informal nickname referring to the crest on Cryolophosaurus; the specimen was formally described as Cryolophosaurus.

References

  1. Hammer, W. R.; Hickerson, W. J. (1994). A Crested Theropod Dinosaur from Antarctica. Science 264(5160): 828-830. American Association for the Advancement of Science (AAAS). doi:10.1126/science.264.5160.828 hammer1994a
  2. Paul, G. S. (2024). The Princeton Field Guide to Predatory Dinosaurs. Princeton University Press.

    Source of the appearance features.

    paul2024b
  3. Nesbitt, S. J.; Smith, N. D.; Irmis, R. B.; Turner, A. H.; Downs, A.; Norell, M. A. (2009). A Complete Skeleton of a Late Triassic Saurischian and the Early Evolution of Dinosaurs. Science 326(5959): 1530-1533. American Association for the Advancement of Science (AAAS). doi:10.1126/science.1180350

    Large theropod phylogeny recovered Cryolophosaurus as a basal tetanuran.

    nesbitt2009a
  4. Marsh, A. D.; Rowe, T. B. (2020). A comprehensive anatomical and phylogenetic evaluation of Dilophosaurus wetherilli (Dinosauria, Theropoda) with descriptions of new specimens from the Kayenta Formation of northern Arizona. Journal of Paleontology 94(S78): 1-103. doi:10.1017/jpa.2020.14

    Dilophosaurus phylogenetic evaluation placed Cryolophosaurus outside Averostra and Tetanurae.

    marsh2020a
  5. Jones, B. (2026). The Princeton Encyclopedia of Dinosaurs: Theropods. Princeton University Press.

    Treats Cryolophosaurus as a neotheropod close to Dilophosaurus, outside Tetanurae.

    jones2026c
  6. 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

    Recovered Cryolophosaurus as the earliest stem tetanuran.

    carrano2012a
  7. Smith, N. D.; Makovicky, P. J.; Hammer, W. R.; Currie, P. J. (2007). Osteology of Cryolophosaurus ellioti (Dinosauria: Theropoda) from the Early Jurassic of Antarctica and implications for early theropod evolution. Zoological Journal of the Linnean Society 151(2): 377-421. doi:10.1111/j.1096-3642.2007.00325.x

    Recovered Cryolophosaurus outside Averostra.

    smith2007b