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Quaesitosaurus

Kurzanov & Bannikov, 1983 kwee-SIET-o-SAWR-us

From Latin 'quaesitus' (extraordinary, sought-after, unusual) + Greek 'sauros' (lizard), meaning 'extraordinary lizard'.

83.6–72.2 million years ago Campanian, Late Cretaceous
Late Cretaceous stages

Quaesitosaurus is a genus of nemegtosaurid sauropod containing only the type species, Q. orientalis, described in 1983. It lived from 72 to 71 million years ago during the Late Cretaceous epoch in the Baruungoyot Formation. With long, low and horse-like with frontally located peg-teeth, the skull of Quaesitosaurus is similar enough to the skull of Diplodocus and its kin to have prompted informed speculation that the missing body was built like those of diplodocids.

Diagnosis

  1. Large 'resonator' depression on posterior side of quadrate bone with thin walls
  2. Inclined canal in base of occipital bone passing from pituitary depression, opening below occipital condyle (unique among sauropods)
  3. Parietal aperture absent
  4. Occipital condyle rounded and inclined downwards
  5. Squamosal bone not in contact with quadratojugal
  6. Maxilla bears nine teeth

Species

Quaesitosaurus orientalis Kurzanov & Bannikov, 1983

Type species

From Latin 'orientalis' meaning 'eastern', referring to the fossil's origin in Mongolia.

Holotype
PIN 3906/2 , Paleontological Institute, Russian Academy of Sciences
Material
Incomplete skull
Horizon
Baruungoyot Formation, Campanian, Late Cretaceous , 83.6–72.2 million years ago
Locality
Shar Tsav, Ömnögovi, Mongolia

References

  1. Averianov, A. O.; Lopatin, A. V. (2020). An unusual new sauropod dinosaur from the Late Cretaceous of Mongolia. Journal of Systematic Palaeontology 18(12): 1009-1032. Informa UK Limited. doi:10.1080/14772019.2020.1716402

    Gives Quaesitosaurus orientalis "from the Shar Tsav locality".

    averianov2020a
  2. Kurzanov, S. M.; Bannikov, A. F. (1983). Nouviy sauropod ys uerchnego mela MNR [New sauropod from the Upper Cretaceous of Mongolia]. Paleontologicheskii Zhurnal 1983(2): 90-96. kurzanov1983a
  3. Jones, B. (2026). The Princeton Encyclopedia of Dinosaurs: Sauropods. Princeton University Press.

    Source of the mass and hip height estimates.

    jones2026b