Open Paleo

Mongolosaurus

Gilmore, 1933 mong-GO-lo-SAWR-us

Named after Mongolia, where the fossil was discovered, combined with Greek 'sauros' (lizard); meaning 'Mongolia lizard'

121.4–100.5 million years ago Aptian–Albian, Early Cretaceous
Early Cretaceous stages

Mongolosaurus is a genus of titanosauriform sauropod dinosaur which lived during the Early Cretaceous of China.

Under dispute

Placed at Somphospondyli incertae sedis. Known largely from teeth and fragmentary material, Mongolosaurus was originally described as a sauropod of undetermined family (Gilmore, 1933). Its redescription (Mannion, 2011) reaffirmed its validity and recovered it as a titanosaurian sauropod, whereas D'Emic (2012) regarded its affinities as equivocal, noting a few euhelopodid- like characters that would place it as a non-titanosaurian somphospondylan against the titanosaur features identified by Mannion. Somphospondyli is the least-inclusive clade both readings accept.

Diagnosis

  1. Teeth tapering and obtusely pointed, slightly flattened on inner side with angularly rounded outer side, bearing low longitudinal carinae (ridges) on either side extending to apex
  2. Tooth carinae faintly serrate (on at least one tooth), distinguishing them from the spatulate, non-serrate teeth of Diplodocus and Pleurocoelus
  3. Pulp cavity continued to top of crown
  4. Atlas intercentrum relatively wider and more deeply excavated on ventral surface than in Diplodocus, with neurapophyses more constricted above base
  5. Third cervical strongly opisthocoelous, lacking true pleurocentral cavities, with capitular facet processes not produced below level of centrum (contrasting with Diplodocus, Helopus, Haplocanthosaurus)
  6. Third cervical with incipient bifid spinous processes indicated by parallel ridges, differing from well-developed spines of Diplodocus, Helopus, and Camarasaurus

Species

Mongolosaurus haplodon Gilmore, 1933

Type species

From Ancient Greek 'haploos' meaning 'single' and 'odon' meaning 'tooth', referring to the single tooth that served as the basis for the original description.

Holotype
AMNH 6710 , American Museum of Natural History
Material
Basioccipital, fragmentary teeth, atlas, and a fragmentary axis and third cervical vertebra
Horizon
On Gong Formation, Aptian–Albian, Early Cretaceous , 121.4–100.5 million years ago
Locality
Hu Khung Ulan, Inner Mongolia, China

References

  1. Gilmore, C. W. (1933). Two new dinosaurian reptiles from Mongolia with notes on some fragmentary specimens. American Museum Novitates 679: 1-20. gilmore1933b
  2. Jones, B. (2026). The Princeton Encyclopedia of Dinosaurs: Sauropods. Princeton University Press.

    Source of the body length estimate.

    jones2026b
  3. Mannion, P. D. (2011). A reassessment of Mongolosaurus haplodon Gilmore, 1933, a titanosaurian sauropod dinosaur from the Early Cretaceous of Inner Mongolia, People's Republic of China. Journal of Systematic Palaeontology 9(3): 355-378. Informa UK Limited. doi:10.1080/14772019.2010.527379

    Redescription of Mongolosaurus; reaffirmed its validity and recovered it as a titanosaurian sauropod.

    mannion2011b
  4. D'Emic, M. D. (2012). The early evolution of titanosauriform sauropod dinosaurs. Zoological Journal of the Linnean Society 166: 624-671. doi:10.1111/j.1096-3642.2012.00853.x

    Regarded Mongolosaurus's affinities as equivocal, noting a few euhelopodid-like characters against the titanosaur features identified by Mannion (2011).

    d'emic2012b