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Nemegtosaurus

Nowinski, 1971 NAY-meg-to-SAWR-us

Named for the Nemegt Basin in the Gobi Desert of Mongolia where the skull was discovered, combined with Greek 'sauros' meaning 'lizard'.

72.2–66.0 million years ago Maastrichtian, Late Cretaceous
Late Cretaceous stages

Nemegtosaurus was a sauropod dinosaur from the Late Cretaceous Period of what is now Mongolia. Measuring an estimated 12-13 m (39-43 ft) long and weighing 20 t (44,000 lb), it was named after the Nemegt Basin in the Gobi Desert, where the remains — a single skull — were found. The skull resembles diplodocoids in being long and low, with pencil-shaped teeth. However, recent work has shown that Nemegtosaurus is in fact a titanosaur, closely related to animals such as Saltasaurus, Alamosaurus, and Rapetosaurus.

Diagnosis

  1. Skull strongly elongated and lightly built with long snout bent downwards
  2. Accessory preorbital foramen absent
  3. Palatine bones very narrow and strongly elongated longitudinally
  4. Ectopterygoid absent
  5. Lacrimal extensive, contributing to margin of external naris
  6. Orbit very large with prefrontal entering margin of orbit and external naris
  7. Supratemporal fossa very small, elongated transversely, open dorsally
  8. Parietal crest very prominent
  9. Occipital condyle placed far anteriorly, directed ventroanteriorly at ~100° to horizontal
  10. Lower jaw very light with mandibular vacuity present (unique among sauropods)
  11. Teeth lanceolate with crown/root length ratio of 2:1

Species

Nemegtosaurus mongoliensis Nowinski, 1971

Type species

Named for Mongolia, where the holotype skull was recovered from the Nemegt Basin.

Holotype
ZPAL MgD-I/9 , Institute of Paleobiology, Polish Academy of Sciences
Material
Nearly complete skull lacking left lacrimal, anterior nasals, most of premaxillae, upper rami of maxillae
Horizon
Nemegt Formation, Maastrichtian, Late Cretaceous , 72.2–66.0 million years ago
Locality
Nemegt, Ömnögovi, Mongolia

References

  1. Nowinski, A. (1971). Nemegtosaurus mongoliensis n. gen., n. sp. (Sauropoda) from the uppermost Cretaceous of Mongolia. Palaeontologia Polonica 25: 57-81. nowinski1971a
  2. Jones, B. (2026). The Princeton Encyclopedia of Dinosaurs: Sauropods. Princeton University Press.

    Source of the hip height estimate.

    jones2026b
  3. Wilson, J. A. (2005). Redescription of the Mongolian sauropod Nemegtosaurus mongoliensis Nowinski (Dinosauria: Saurischia) and comments on Late Cretaceous sauropod diversity. Journal of Systematic Palaeontology 3(3): 283-318. doi:10.1017/s1477201905001628

    Redescription of the holotype skull.

    wilson2005a