| Chilantaisaurus Temporal range: Late Cretaceous, 92 Ma |
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| Restoration of C. tashuikouensis | |
| Scientific classification | |
| Kingdom: | Animalia |
| Phylum: | Chordata |
| Class: | Reptilia |
| Superorder: | Dinosauria |
| Order: | Saurischia |
| Suborder: | Theropoda |
| Infraorder: | Carnosauria |
| Superfamily: | Allosauroidea |
| Family: | Neovenatoridae |
| Genus: | Chilantaisaurus Hu, 1964 |
| Species | |
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Chilantaisaurus ("Ch'i-lan-t'ai lizard") is a genus of neovenatorid theropod dinosaur 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] Recently, Brusatte et al. (2010) estimated it to weight 6,000 kilograms (13,000 lb).[3]
Hu considered Chilantaisaurus to be a carnosaur related to Allosaurus,[4] though some subsequent studies suggested that it may be a spinosauroid, possibly a primitive member of the spinosaurid family (Sereno, 1998; Chure, 2002; Rauhut, 2001) because it had large claw 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.[5] 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.[6] 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]
Several species have been described based on very poor remains. Chilantaisaurus? sibiricus is based on a single distal metatarsal IV from the Turginskaya Svita of the Buryat Autonomous Soviet Socialist Republic, Russia, dating to the Early Cretaceous (Berriasian-Hauterivian).[7][8] It is poorly described, so its relationships cannot be accurately determined (Chure, 2002). "Chilantaisaurus" maortuensis was reclassified as Shaochilong maortuensis in 2009.[6] Bones attributed to "Chilantaisaurus" zheziangensis come from a therizinosaur, and may in fact come from the same individual as the type specimen of Nanshiungosaurus.