Chilantaisaurus Temporal range: Late Cretaceous, | |
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Skeleton reconstruction of Chilantaisaurus tashuikouensis | |
Scientific classification | |
Domain: | Eukaryota |
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 | |
Chilantaisaurus ("Jilantai Salt Lake lizard" [1] ) is a genus of large theropod dinosaur, possibly a neovenatorid or a primitive coelurosaur, from the Late Cretaceous Ulansuhai Formation of China (Turonian age, about 92 million years ago). The type species, C. tashuikouensis, was described by Hu in 1964.
Chilantaisaurus was a large theropod, measuring 11 metres (36 ft) long and weighing 2.5–4 metric tons (2.8–4.4 short tons). [2] [3] [4] While Brusatte et al. (2010) estimated that Chilantaisaurus might have weighed about 6 metric tons (6.6 short tons) based on femur length similar to that of Tyrannosaurus , [5] Persons et al. (2020) argued that greater femoral circumference indicates the greater capacity to withstand greater locomotor loads, not greater body mass. [6]
Hu considered Chilantaisaurus to be a carnosaur related to Allosaurus , [1] 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. [2] Phylogenetic analysis published by Porfiri et al. in 2018 recovered Chilantaisaurus as a primitive 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 discovered in 1915 in 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]
An additional species named in 1979, "Chilantaisaurus" zheziangensis, based on bones from the foot and a partial tibia, [13] is actually a therizinosaur taxon. [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]
Carnosauria is an extinct group of carnivorous theropod dinosaurs that lived during the Jurassic and Cretaceous periods.
Tetanurae is a clade that includes most theropod dinosaurs, including megalosauroids, allosauroids, tyrannosauroids, ornithomimosaurs, compsognathids and maniraptorans. Tetanurans are defined as all theropods more closely related to modern birds than to Ceratosaurus and contain the majority of predatory dinosaur diversity. Tetanurae likely diverged from its sister group, Ceratosauria, during the late Triassic. Tetanurae first appeared in the fossil record by the Early Jurassic about 190 mya and by the Middle Jurassic had become globally distributed.
Neovenator is a genus of carcharodontosaurian theropod dinosaur. It is known from several skeletons found in the Early Cretaceous (Hauterivian-Barremian) Wessex Formation on the south coast of the Isle of Wight, southern England. It is one of the best known theropod dinosaurs from the Early Cretaceous of Europe.
Fukuiraptor was a medium-sized megaraptoran theropod dinosaur of the Early Cretaceous epoch that lived in what is now Japan. Fukuiraptor is known from the Kitadani Formation and possibly also the Sebayashi Formation.
Carcharodontosauridae is a group of carnivorous theropod dinosaurs. In 1931, Ernst Stromer named Carcharodontosauridae as a family, which, in modern paleontology, indicates a clade within Carnosauria. Carcharodontosaurids include some of the largest land predators ever known: Giganotosaurus, Mapusaurus, Carcharodontosaurus, and Tyrannotitan all rivaled Tyrannosaurus in size. Estimates give a maximum weight of 8–10 metric tons for the largest carcharodontosaurids, while the smallest carcharodontosaurids were estimated to have weighed at least 500 kilograms (1,100 lb).
Deltadromeus is a genus of theropod dinosaur from the Aoufous Formation of Morocco.
Megaraptor is a genus of large theropod dinosaur that lived in the ages of the Late Cretaceous. Its fossils have been discovered in the Patagonian Portezuelo Formation of Argentina, South America. Initially thought to have been a giant dromaeosaur-like coelurosaur, it was classified as a neovenatorid allosauroid in previous phylogenies, but more recent phylogeny and discoveries of related megaraptoran genera has placed it as either a basal tyrannosauroid or a basal coelurosaur with some studies still considering it a neovenatorid.
Megalosauroidea is a superfamily of tetanuran theropod dinosaurs that lived from the Middle Jurassic to the Late Cretaceous period. The group is defined as Megalosaurus bucklandii and all taxa sharing a more recent common ancestor with it than with Allosaurus fragilis or Passer domesticus. Members of the group include Spinosaurus, Megalosaurus, and Torvosaurus. They are possibly paraphyletic in nature with respect to Allosauroidea.
Ekrixinatosaurus is a genus of abelisaurid theropod which lived approximately 100 to 97 million years ago during the Late Cretaceous period. Its fossils have been found in Argentina. Only one species is currently recognized, Ekrixinatosaurus novasi, from which the specific name honors of Dr. Fernando Novas for his contributions to the study of abelisaurid theropods, while the genus name refers to the dynamiting of the holotype specimen. It was a large abelisaur, measuring between 6.5 and 8 m in length and weighing 800 kg (1,800 lb).
Allosauroidea is a superfamily or clade of theropod dinosaurs which contains four families — the Metriacanthosauridae, Allosauridae, Carcharodontosauridae, and Neovenatoridae. Allosauroids, alongside the family Megalosauroidea, were among the apex predators that were active during the Middle Jurassic to Late Cretaceous periods. The most famous and best understood allosauroid is the North American genus Allosaurus.
Orkoraptor is a genus of medium-sized megaraptoran theropod dinosaur from the late Cretaceous Period of Argentina. It is known from incomplete fossil remains including parts of the skull, teeth, tail vertebrae, and a partial tibia. The specialized teeth resemble those of some maniraptoriform theropods, namely the deinonychosaurs and compsognathids. This and other anatomical features led the authors who described it to suggest that it was a maniraptoran coelurosaur. However, subsequent studies found it to be a megaraptoran. Found in the Cerro Fortaleza Formation of Southern Patagonia, it is one of the southernmost carnivorous dinosaurs known from South America.
Aerosteon is a genus of megaraptoran dinosaur from the Late Cretaceous period of Argentina. Its remains were discovered in 1996 in the Anacleto Formation, which is from the late Campanian. The type and only known species is A. riocoloradensis. Its specific name indicates that its remains were found 1 km north of the Río Colorado, in Mendoza Province, Argentina.
Bahariasauridae is a potential family of averostran theropods that might include a handful of African and South American genera, such as Aoniraptor, Bahariasaurus, Deltadromeus, and Gualicho. The placement of these theropods is controversial, with some studies placing them as basal ceratosaurs possibly related to Noasauridae, others classifying them as megaraptorans, basal neovenatorids, or basal coelurosaurs. There is also a possibility the group might not be monophyletic, as a monograph on the vertebrate diversity in the Kem Kem Beds published in 2020 found Bahariasaurus to be nomen dubium. In the same paper Deltadromeus is classified as an noasaurid, a result also recovered by some previous studies. A 2024 analysis found Aoniraptor, Bahariasaurus, Deltadromeus, Elaphrosaurus and Gualicho to form a monophyletic clade at the base of Ceratosauria.
Shaochilong is an extinct genus of carcharodontosaurid dinosaur from the mid-Cretaceous Ulansuhai Formation of China. The type species, S. maortuensis, was originally named Chilantaisaurus maortuensis, but was re-described and reclassified in 2009. It was one of the last known carcharodontosaurids to walk the earth. Alongside Mapusaurus from Argentina, they were the only members of the family to live until the end of the Turonian epoch.
Australovenator is a genus of megaraptoran theropod dinosaur from Cenomanian -age Winton Formation of Australia. It is known from partial cranial and postcranial remains which were described in 2009 by Scott Hocknull and colleagues, although additional descriptions and analyses continue to be published. It is the most complete predatory dinosaur discovered in Australia. It has been suggested that Australovenator is a sister taxon to Fukuiraptor, although some phylogenetic analyses find it to be a more derived member of the Megaraptora, possibly being part of the main Megaraptoridae family itself.
Neovenatoridae is a proposed clade of carcharodontosaurian dinosaurs uniting some primitive members of the group such as Neovenator with the Megaraptora, a group of theropods with controversial affinities. Other studies recover megaraptorans as basal coelurosaurs unrelated to carcharodontosaurs. Other theropods with uncertain affinities such as Gualicho, Chilantaisaurus and Deltadromeus are also sometimes included.
Megaraptora is a clade of carnivorous theropod dinosaurs. Its derived members, the Megaraptoridae are noted for their large hand claws and powerfully-built forelimbs, which are usually reduced in size in other large theropods.
Gualicho is a genus of theropod dinosaur. The type species is Gualicho shinyae. It lived in what is now northern Patagonia, on what was then a South American island continent split off from the supercontinent Gondwana. The fossils were found in the Huincul Formation, dating to the late Cenomanian-early Turonian age of the upper Cretaceous Period, around 91 million years ago.
Tratayenia is an extinct genus of megaraptoran theropod dinosaurs known from remains found in the Santonian-age Bajo de la Carpa Formation of Argentina. The type and only species, Tratayenia rosalesi, was described in March 2018.