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Supersaurus

Jensen, 1985 SOO-per-SAWR-us

From Latin super, "above" or "super", combined with Greek sauros, "lizard" — means "super lizard", reflecting its enormous size

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

Supersaurus is a genus of diplodocid sauropod dinosaur that lived in North America during the Late Jurassic period. The type species, S. vivianae, was first discovered by Vivian Jones of Delta, Colorado, in the middle Morrison Formation of Colorado in 1972. The fossil remains came from the Brushy Basin Member of the formation, dating between 153 and 145 million years ago. It is among the longest dinosaurs ever discovered, with the three known specimens reaching 33-40 meters (108-131 ft) in length, with the largest individual possibly exceeding 40 meters (130 ft) in size. Mass estimates for the WDC and BYU specimens tend to be around 35-44 metric tons (39-49 short tons) in body mass. A potential second species, S. lourinhanensis (Dinheirosaurus), is known from Portugal and has been dated to a similar time.

Diagnosis

  1. Elongate cervical vertebrae (elongation index 4-7) with extreme narrowing of the ventral body at midlength and well-developed parallel ventral keels
  2. Cervicals with a small ventral pleurocoel between the parapophyses bearing dual pneumatopores divided by a septum; lateral pleurocoels simple, shallow, with small pneumatopores
  3. Posterior dorsal vertebrae opisthocoelous, with tall neural spines (more than half the vertebral height) and a reduced neural arch
  4. Anterior dorsal centra with a moderate midline keel and shallow lateral sulci
  5. Anterior caudal vertebrae with a prominent ventral keel and shallow pleurocoels
  6. Ribs pneumatized, with anteroposteriorly expanded shafts
  7. Scapular blade expanded dorsally; deltoid ridge perpendicular to the acromial ridge

Species

Supersaurus vivianae Jensen, 1985

Type species

Named for Vivian Jones of Delta, Colorado, the amateur fossil hunter who first discovered the remains in the Morrison Formation in 1972.

Holotype
BYU 9025 , Earth Sciences Museum, Brigham Young University
Material
Scapulocoracoid.
Notes
Which scapulocoracoid bears the name is unsettled. The erecting paper gives BYU 5500, renumbered BYU 9025, and calls it a right scapulocoracoid. Lovelace and colleagues (2008) contradict themselves: their text gives the holotype as BYU 12962, "a large diplodocid left scapulocoracoid", their Table 1 lists BYU 9025 as the left scapulocoracoid and holotype with BYU 12962 as its right mate, and their Fig. 10 shows BYU 9025 as a right scapulocoracoid. The number follows the erecting paper.
Horizon
lower Brushy Basin Member, Morrison Formation, Kimmeridgian–Tithonian, Late Jurassic , 154.8–143.1 million years ago
Locality
Dry Mesa Quarry, Colorado, United States

Synonyms of the genus

Name Type Reason
Dystylosaurus junior subjective D. edwini, originally described from a dorsal vertebra found near the Supersaurus quarry, is now considered referable to Supersaurus.
Jensenosaurus nomen nudum Informal name used for material now considered referable to Supersaurus.
Ultrasauros junior subjective Now widely treated as a junior synonym of Supersaurus.

Notable specimens

  • “Jimbo”

    WDC DMJ-021 Wyoming Dinosaur Center Found 1996 by Brandon Flyr and Bart Lesco ontogeny

    Much more complete specimen, about 30 percent of the skeleton, found while hiking in Converse County, Wyoming; nicknamed Jimbo. A 2024 study found it skeletally mature and so old its exact age could not be reliably calculated, making it possibly the oldest dinosaur known thus far.

    Lovelace et al. (2008)Woodruff et al. (2024)

  • BYU 9024

    Earth Sciences Museum, Brigham Young University largest individual

    A large cervical vertebra measuring 1.38 meters in length, the longest cervical known, from the Dry Mesa Quarry and reassigned to Supersaurus. One estimate gives an approximate length up to 50 meters, which would have made it the longest animal to ever live.

    Jensen (1987)Curtice (2021)

References

  1. Lovelace, D. M.; Hartman, S. A.; Wahl, W. R. (2008). Morphology of a specimen of Supersaurus (Dinosauria, Sauropoda) from the Morrison Formation of Wyoming, and a re-evaluation of diplodocid phylogeny. Arquivos do Museu Nacional 65(4): 527-544. lovelace2008a
  2. Woodruff, D. C.; Curtice, B. D.; Foster, J. R. (2024). Seis-ing up the Super-Morrison formation sauropods. Journal of Anatomy 247(3-4): 682-698. doi:10.1111/joa.14108 woodruff2024a
  3. Jensen, J. A. (1987). New brachiosaur material from the Late Jurassic of Utah and Colorado. The Great Basin Naturalist 47(4): 592-608. jensen1987a
  4. Curtice, B. (2021). New Dry Mesa Dinosaur Quarry Supersaurus vivianae (Jensen 1985) axial elements provide additional insight into its phylogenetic relationships and size, suggesting an animal that exceeded 39 meters in length. Society of Vertebrate Paleontology 81st Annual Meeting.

    Conference abstract.

    curtice2021a
  5. Jensen, J. A. (1985). Three new sauropod dinosaurs from the Upper Jurassic of Colorado. The Great Basin Naturalist 45(4): 697-709. doi:10.5962/bhl.part.4439 jensen1985a
  6. Paul, G. S. (2024). The Princeton Field Guide to Dinosaurs (3rd ed.). Princeton University Press.

    Source of the mass estimate.

    paul2024a
  7. Jones, B. (2026). The Princeton Encyclopedia of Dinosaurs: Sauropods. Princeton University Press.

    Source of the hip height estimate, and the appearance features.

    jones2026b