Chilantaisaurus

Hu, 1964 jee-LAHN-tie-SAWR-us

Named after Jilantai (also romanized as Chilantai) Salt Lake in Inner Mongolia, China, where the fossils were found, + Greek sauros ('lizard'), meaning 'Jilantai Salt Lake lizard'.

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

Early Cretaceous stages

Chilantaisaurus is an extinct genus of large theropod dinosaur that lived in present-day China during the Late Cretaceous period. It was described by Chinese paleontologist Hu Show-Yung in 1964. The genus contains a single valid species, C. tashuikouensis, though several other species have been assigned to the genus. C. tashuikouensis is known from a single, incomplete postcranial skeleton, the holotype specimen. This specimen was found by a joint Sino-Soviet expedition to Inner Mongolia in rock layers coming from the Ulansuhai Formation. This indicates these fossils date to the Santonian or Campanian stages of the Cretaceous period, around 85.7 to 72.2 million years ago. However, the age of the Ulansuhai Formation is debated.

Under dispute

Chilantaisaurus tashuikouensis is a large, fragmentary theropod whose position is highly unstable. It has been recovered as a basal carcharodontosaurian or neovenatorid close to Neovenator (Benson and colleagues, 2010; Carrano and colleagues, 2012; Rauhut and colleagues, 2024; Kellermann and colleagues, 2025), as a non-megaraptoran tetanuran of uncertain affinity (Novas and colleagues, 2013), and as a megaraptoran within Tyrannosauroidea (Naish and Cau, 2022). Because these hypotheses span Allosauroidea and Coelurosauria, it is placed conservatively at Avetheropoda incertae sedis.

Diagnosis

Humerus massive and elongate, with humero-femoral ratio of 0.487, much greater than any known carnosaur
Ungual phalanx of digit I especially large, strongly and regularly curved, with concave proximal articular surface
Tibia shorter than femur, with tibio-femoral ratio of 0.80
Metatarsals short and stout relative to femur, not closely appressed, with unreduced metatarsal III shaft

Species

Chilantaisaurus tashuikouensis Hu, 1964

Type species

Named for the Tashuikou site in Inner Mongolia, China, where the holotype fossils were discovered.

Lectotype: IVPP V2884 , Institute of Vertebrate Paleontology and Paleoanthropology
Material: A right humerus, ungual of digit I, fragmentary left ilium, both femora, both tibiae, right fibula, and right metatarsals II–IV plus left metatarsals III–IV, all from a single individual.
Horizon: Miaogou Formation, Aptian–Albian, Early Cretaceous , 121.4–100.5 million years ago
Locality: Tashuikou, Inner Mongolia, China Hu (1964) gives the type locality as Dashuigou, which Carrano and colleagues (2012) identify with Tashuikou. Hao and colleagues (2024) discontinued the Dashuigou Formation and placed its strata in the Miaogou Formation, so the horizon follows; none of the works cited for this taxon states that combination outright. The Ulansuhai assignment rests on a radiometric date from basalts some 200 km away and is not followed. The Turonian goes with it: Benson and colleagues (2010) give "Ulansuhai Formation (?Turonian, Late Cretaceous)" after Hu (1964), while Hao and colleagues (2024) date the Miaogou "Aptian-Albian".

References

Hu, S. Y. (1964). [Carnosaurian remains from Alashan, Inner Mongolia]. Vertebrata PalAsiatica 8(1): 42-63. hu1964a
Jones, B. (2026). The Princeton Encyclopedia of Dinosaurs: Theropods. Princeton University Press.
Source of the hip height estimate.
jones2026c
Naish, D.; Cau, A. (2022). The osteology and affinities of Eotyrannus lengi, a tyrannosauroid theropod from the Wealden Supergroup of southern England. PeerJ 10: e12727. PeerJ. doi:10.7717/peerj.12727
Recovered Chilantaisaurus as a megaraptoran within Tyrannosauroidea.
naish2022a
Carrano, M. T.; Benson, R. B. J.; Sampson, S. D. (2012). The phylogeny of Tetanurae (Dinosauria: Theropoda). Journal of Systematic Palaeontology 10(2): 211-300. Informa UK Limited. doi:10.1080/14772019.2011.630927
Recovered Chilantaisaurus's affinities within Tetanurae in a broad theropod phylogenetic analysis.
carrano2012a
Rauhut, O. W. M.; Bakirov, A. A.; Wings, O.; Fernandes, A. E.; Hübner, T. R. (2024). A new theropod dinosaur from the Callovian Balabansai Formation of Kyrgyzstan. Zoological Journal of the Linnean Society 201(4). Oxford University Press (OUP). doi:10.1093/zoolinnean/zlae090
New theropod description's phylogenetic analysis bore on Chilantaisaurus's tetanuran placement.
rauhut2024a
Kellermann, M.; Cuesta, E.; Rauhut, O. W. M. (2025). Re-evaluation of the Bahariya Formation carcharodontosaurid (Dinosauria: Theropoda) and its implications for allosauroid phylogeny. PLOS ONE 20(1): e0311096. Public Library of Science (PLoS). doi:10.1371/journal.pone.0311096
Treated Chilantaisaurus as an indeterminate tetanuran of uncertain affinity in its re-evaluation.
kellermann2025a
Novas, F. E.; Agnolín, F. L.; Ezcurra, M. D.; Porfiri, J.; Canale, J. I. (2013). Evolution of the carnivorous dinosaurs during the Cretaceous: The evidence from Patagonia. Cretaceous Research 45: 174-215.
Placed Chilantaisaurus as a non-megaraptoran tetanuran of uncertain affinity in this review.
novas2013a
Benson, R. B. J.; Carrano, M. T.; Brusatte, S. L. (2010). A new clade of archaic large-bodied predatory dinosaurs (Theropoda: Allosauroidea) that survived to the latest Mesozoic. Naturwissenschaften 97(1): 71-78. doi:10.1007/s00114-009-0614-x
Recover Chilantaisaurus as a basal carcharodontosaurian or neovenatorid near Neovenator, and place the holotype in the Ulansuhai Formation, which the erecting paper did not name.
benson2010d
Hao, M.; Li, Z.; Wang, Z.; Wang, S.; Ma, F.; Qinggele; Logan King, J.; Pei, R.; Zhao, Q.; Xu, X. (2024). A new oviraptorosaur from the Lower Cretaceous Miaogou Formation of western Inner Mongolia, China. Cretaceous Research 167(78): 106023. Elsevier BV. doi:10.1016/j.cretres.2024.106023
Discontinues the Dashuigou Formation and places its strata in the Miaogou Formation.
hao2024a