Chilantaisaurus

Chilantaisaurus ("Ch'i-lan-t'ai lizard") is a genus of large theropod dinosaur, possibly a neovenatorid or basal coelurosaur, from the late Cretaceous Ulansuhai Formation of China (Turonian stage, about 92 million years ago). The type species, C. tashuikouensis, was described by Hu in 1964. Chilantaisaurus was a large theropod, estimated as weighing between 2.5 metric tons (2.8 short tons)[1] and 4 metric tons (4.4 short tons).[2] In 2010, Brusatte et al. estimated it to weigh 6,000 kilograms (13,000 lb), based on femur length measurements.[3] It is estimated to be around 11 m (36 ft) to 13 m (43 ft) long.[4][5]

Chilantaisaurus
Temporal range: Late Cretaceous, 92 Ma
Chilantaisaurus.jpg
Restoration of C. tashuikouensis
Scientific classification edit
Kingdom: Animalia
Phylum: Chordata
Clade: Dinosauria
Clade: Saurischia
Clade: Theropoda
Clade: Avetheropoda
Genus: Chilantaisaurus
Hu, 1964
Species:
C. tashuikouensis
Binomial name
Chilantaisaurus tashuikouensis
Hu, 1964

ClassificationEdit

Hu considered Chilantaisaurus to be a carnosaur related to Allosaurus,[6] though some subsequent studies suggested that it may be a spinosauroid, possibly a primitive member of the spinosaurid family (Sereno, 1998; Chure, 2000; Rauhut, 2001) because it had large claws on the forelimbs thought to be unique to that group. Other studies suggested that it could be a member of an alternate offshoot of neotetanuran theropods, with some similarities to allosauroids, spinosauroids, and coelurosaurians.[7] A 2009 study noted that it was difficult to rule out the possibility that Chilantaisaurus was the same animal as the carnosaur Shaochilong, which is from the same geological formation. However, they did note an enormous size difference between the two.[8] Further study by Benson, Carrano and Brusatte found that it was not as closely related to Shaochilong as first thought, but that it was a carnosaur (of the family Neovenatoridae), closely related to Allosaurus as Hu had initially thought.[1] Phylogenetic analysis published by Porfiri et al. in 2018 recovered Chilantaisaurus as a basal coelurosaurian.[9]

Several species have been described based on very poor remains. The species "Chilantaisaurus" sibiricus (previously informally known as either Allosaurus? sibiricus or Antrodemus? sibiricus) is based on a single distal metatarsal from the Turginskaya Svita of the Buryat Autonomous Soviet Socialist Republic, Russia, dating to the Early Cretaceous periods (Berriasian to Hauterivian stages).[10][11][12] It is poorly described, so its relationships cannot be accurately determined (Chure, 2000) and its placement as a species of Chilantaisaurus is highly questionable. "Chilantaisaurus" maortuensis was reclassified as Shaochilong maortuensis in 2009.[8] "Chilantaisaurus" zheziangensis, based on bones from the foot,[13] is actually a therizinosaur.[14][15]

The cladogram below follows a 2016 analysis by Sebastián Apesteguía, Nathan D. Smith, Rubén Juarez Valieri, and Peter J. Makovicky based on the dataset of Carrano et al. (2012).[16]

Allosauroidea 

Metriacanthosauridae  

Allosauria

Allosauridae  

Carcharodontosauria

Carcharodontosauridae  

Neovenatoridae

Deltadromeus  

Gualicho  

Neovenator  

Chilantaisaurus  

Megaraptora  

ReferencesEdit

  1. ^ a b 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. Bibcode:2010NW.....97...71B. doi:10.1007/s00114-009-0614-x. PMID 19826771. S2CID 22646156.
  2. ^ Paul, G.S. (1988). Predatory Dinosaurs of the World. New York: Simon and Schuster. p. 314.
  3. ^ Brusatte, S.L.; Chure, D.J.; Benson, R.B.J.; Xu, X. (2010). "The osteology of Shaochilong maortuensis, a carcharodontosaurid (Dinosauria: Theropoda) from the Late Cretaceous of Asia" (PDF). Zootaxa. 2334: 1–46. doi:10.11646/zootaxa.2334.1.1.
  4. ^ Paul, G.S., 2010, The Princeton Field Guide to Dinosaurs, Princeton University Press.
  5. ^ Holtz, Thomas R. Jr. (2012) Dinosaurs: The Most Complete, Up-to-Date Encyclopedia for Dinosaur Lovers of All Ages, Winter 2011 Appendix
  6. ^ Hu, S.-Y. (1964). "Carnosaurian remains from Alashan, Inner Mongolia." Vertebrata PalAsiatica, 8: 42–63. [In Chinese, with English summary]
  7. ^ Benson, R.B.; Xu, X. (2008). "The anatomy and systematic position of the theropod dinosaur Chilantaisaurus tashuikouensis Hu, 1964 from the Early Cretaceous of Alanshan, People's Republic of China" (PDF). Geological Magazine. published online (6): 778–789. Bibcode:2008GeoM..145..778B. doi:10.1017/S0016756808005475. S2CID 53356119.
  8. ^ a b Brusatte, S., Benson, R., Chure, D., Xu, X., Sullivan, C., and Hone, D. (2009). "The first definitive carcharodontosaurid (Dinosauria: Theropoda) from Asia and the delayed ascent of tyrannosaurids." Naturwissenschaften, doi:10.1007/s00114-009-0565-2
  9. ^ Juan D. Porfiri; Rubén D. Juárez Valieri; Domenica D.D. Santos; Matthew C. Lamanna (2018). "A new megaraptoran theropod dinosaur from the Upper Cretaceous Bajo de la Carpa Formation of northwestern Patagonia". Cretaceous Research. 89: 302–319. doi:10.1016/j.cretres.2018.03.014.
  10. ^ Riabinin, 1915. Zamtka o dinozavry ise Zabaykalya [A note on a dinosaur from the trans-Baikal region]. Trudy Geologichyeskago Muszeyah Imeni Petra Velikago Imperatorskoy Academiy Nauk. 8(5), 133-140.
  11. ^ Weishampel, David B; et al. (2004). "Dinosaur distribution (Early Cretaceous, Asia)." In: Weishampel, David B.; Dodson, Peter; and Osmólska, Halszka (eds.): The Dinosauria, 2nd, Berkeley: University of California Press. Pp. 563-570. ISBN 0-520-24209-2.
  12. ^ "Coelurosauria". theropoddatabase.com.
  13. ^ Z. Dong. 1979. Cretaceous dinosaurs of Hunan, China. Mesozoic and Cenozoic Red Beds of South China: Selected Papers from the "Cretaceous-Tertiary Workshop", Institute of Vertebrate Paleontology and Paleoanthropology & Nanjing Institute of Paleontology (eds.), Science Press, Nanxiong, China 342-350
  14. ^ M.-p. Qian, Z.-y. Zhang, Y. Jiang, Y.-g. Jiang, Y.-j. Zhang, R. Chen, and G.-f. Xing. 2012. [Cretaceous therizinosaurs in Zhejiang of eastern China]. Journal of Geology 36(4):337-348
  15. ^ L. E. Zanno. 2010. Osteology of Falcarius utahensis (Dinosauria: Theropoda): characterizing the anatomy of basal therizinosaurs. Zoological Journal of the Linnean Society 158(1):196-230
  16. ^ Sebastián Apesteguía; Nathan D. Smith; Rubén Juárez Valieri; Peter J. Makovicky (2016). "An Unusual New Theropod with a Didactyl Manus from the Upper Cretaceous of Patagonia, Argentina". PLOS ONE. 11 (7): e0157793. Bibcode:2016PLoSO..1157793A. doi:10.1371/journal.pone.0157793. PMC 4943716. PMID 27410683.