Open Paleo

Erliansaurus

Xu et al., 2002 ur-lee-yen-sor-us

From Erlian (the town of Erlian/Erenhot in Inner Mongolia, China, near the discovery site) + Greek sauros (lizard): 'Erlian lizard'.

89.8–66.0 million years ago Coniacian–Maastrichtian, Late Cretaceous
Late Cretaceous stages

Erliansaurus is a genus of therizinosaurian theropod dinosaur that lived in Asia during the Late Cretaceous period in what is now Nei Mongol, Iren Dabasu Formation.

Under dispute

Erliansaurus is an intermediate therizinosaur that falls inside or outside Therizinosauridae according to the definition used. Zanno (2010) and Hartman and colleagues (2019) recover it below the derived clade of Nothronychus, Segnosaurus and Erlikosaurus, outside the family as Zanno and colleagues (2009) define it. Kobayashi and colleagues (2022) recover it in the same position, with Neimongosaurus, and include it in Therizinosauridae under their stem-based definition. It is placed in Therizinosauroidea.

Diagnosis

  1. Enlarged nutritional foramen on anterior caudal vertebrae (large, oval, sharp-rimmed opening on lateral surface of caudal centra, unknown in other theropods)
  2. Crest-like posterior trochanter on humerus, 25 mm in length with wedge-shaped cross-section, bordered medially by a shallow oval depression
  3. Rugose swelling located dorsal to the ischiadic peduncle on the lateral surface of the ilium, anterior to the heavy posterodistal crest
  4. Posterior margin of fibular proximal end significantly higher than anterior margin, forming a concave sloping dorsal margin in medial/lateral views
  5. Distally located hypertrophied anterior trochanter on fibula at mid-shaft, projecting laterally rather than anteriorly

Species

Erliansaurus bellamanus Xu et al., 2002

Type species

From Latin 'bellus' meaning 'beautiful' and 'manus' meaning 'hand', in reference to the exquisite preservation of the forelimb in the holotype.

Holotype
LH V0002 , Long Hao Institute of Geology and Palaeontology
Material
Partial skeleton preserving much postcranial material: five vertebrae, left forelimb lacking carpus, partial right ilium, ischium and pubis fragments, right femur, both tibiae, right fibula, partial metatarsals.
Horizon
Iren Dabasu Formation, Coniacian–Maastrichtian, Late Cretaceous , 89.8–66.0 million years ago
Locality
Sanhangobi, Inner Mongolia, China

References

  1. Xu, X.; Zhang, Z. H.; Sereno, P. C.; Zhao, X. J.; Kuang, X. W.; Han, J.; Tan, L. (2002). A new therizinosauroid (Dinosauria, Theropoda) from the Upper Cretaceous Iren Dabasu Formation of Nei Mongol. Vertebrata PalAsiatica 40(3): 228-240. xu2002c
  2. Jones, B. (2026). The Princeton Encyclopedia of Dinosaurs: Theropods. Princeton University Press.

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

    jones2026c
  3. Zanno, L. E. (2010). A taxonomic and phylogenetic re-evaluation of Therizinosauria (Dinosauria: Maniraptora). Journal of Systematic Palaeontology 8(4): 503-543. doi:10.1080/14772019.2010.488045

    Recovered Erliansaurus outside Therizinosauridae, as an intermediate therizinosauroid.

    zanno2010a
  4. Hartman, S.; Mortimer, M.; Wahl, W. R.; Lomax, D. R.; Lippincott, J.; Lovelace, D. M. (2019). A new paravian dinosaur from the Late Jurassic of North America supports a late acquisition of avian flight. PeerJ 7: e7247. PeerJ. doi:10.7717/peerj.7247

    Recovered Erliansaurus outside a clade of Nanshiungosaurus, Nothronychus, Erlikosaurus and Segnosaurus.

    hartman2019a
  5. Kobayashi, Y.; Takasaki, R.; Fiorillo, A. R.; Chinzorig, T.; Hikida, Y. (2022). New therizinosaurid dinosaur from the marine Osoushinai Formation (Upper Cretaceous, Japan) provides insight for function and evolution of therizinosaur claws. Scientific Reports 12(1). Springer Science and Business Media LLC. doi:10.1038/s41598-022-11063-5

    Under broader definition, recovered Erliansaurus with Neimongosaurus as the family's most basal clade.

    kobayashi2022a
  6. Kobayashi, Y.; Zelenitsky, D. K.; Fiorillo, A. R.; Chinzorig, T. (2025). Didactyl therizinosaur with a preserved keratinous claw from the Late Cretaceous of Mongolia. iScience 28(4). Elsevier BV. doi:10.1016/j.isci.2025.112141 kobayashi2025a
  7. Zanno, L. E.; Gillette, D. D.; Albright, L. B.; Titus, A. L. (2009). A new North American therizinosaurid and the role of herbivory in 'predatory' dinosaur evolution. Proceedings of the Royal Society B: Biological Sciences 276(1672): 3505-3511. The Royal Society. doi:10.1098/rspb.2009.1029

    Defined Therizinosauridae as the least inclusive clade containing Nothronychus, Segnosaurus, Erlikosaurus and Therizinosaurus.

    zanno2009a