Coelurids Temporal range: Late Jurassic, | |
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Reconstructed skeleton of Coelurus | |
Scientific classification ![]() | |
Domain: | Eukaryota |
Kingdom: | Animalia |
Phylum: | Chordata |
Clade: | Dinosauria |
Clade: | Saurischia |
Clade: | Theropoda |
Clade: | Tyrannoraptora |
Family: | † Coeluridae Marsh, 1881 |
Genera | |
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Coeluridae is a historically unnatural group of generally small, carnivorous dinosaurs from the late Jurassic Period. For many years, any small Jurassic or Cretaceous theropod that did not belong to one of the more specialized families recognized at the time was classified with the coelurids, creating a confusing array of 'coelurid' theropods that were not closely related. Although they have been traditionally included in this family, there is no evidence that any of these primitive coelurosaurs form a natural group with Coelurus , the namesake of Coeluridae, to the exclusion of other traditional coelurosaur groups.
Before the use of phylogenetic analyses, Coeluridae and Coelurosauria were taxonomic wastebaskets used for small theropods that did not belong to other groups; thus, they accumulated many dubious genera. [1] [2] As late as the 1980s, popular books recognized over a dozen "coelurids", including such disparate forms as the noasaurid Laevisuchus and the oviraptorosaurian Microvenator , and considered them descendants of the coelophysids. [3] A wastebasket Coeluridae lingered into the early 1990s in some sources [4] (and appears in at least one 2006 source) [5] but since then it has only been recognized in a much reduced form. [6] [7]
In 2003, O.W.M. Rauhut, using a cladistic analysis, found Coeluridae to include Coelurus (Late Jurassic, North America), Compsognathus (Late Jurassic, Europe), Sinosauropteryx (Early Cretaceous, Asia) and an unnamed Compsognathus -like form (Early Cretaceous, South America; this dinosaur has since been placed in the new genus Mirischia ). Rauhut considered coelurids to be a monophyletic group of basal coelurosaurs, characterized by evolutionary reversals in some aspects of the vertebrae to the more primitive theropod condition. [6] However, he and other authors have not since found this result. [7] [8] [9] Phil Senter proposed in 2007 that Coelurus and Tanycolagreus were the only coelurids, and were actually tyrannosauroids. [7]
Coeluridae received a formal phylogenetic definition in 2015, when it was defined as all species more closely related to Coelurus fragilis than to Proceratosaurus bradleyi, Tyrannosaurus rex, Allosaurus fragilis, Compsognathus longipes, Ornithomimus edmontonicus, or Deinonychus antirrhopus by Hendrickx, Hartman and Mateus. [10] It remains unclear whether or not this group contains any species other than Coelurus itself, and while Tanycolagreus is often included, support for this relationship has been weak in most of the studies that recovered it. [11]
In 2024, Cau recovered Coeluridae as the basalmost family of maniraptoromorphs, including few of its traditional members; in addition to Coelurus , it contains Shishugounykus (traditionally a basal alvarezsaur), Phuwiangvenator and Vayuraptor (sometimes considered to be early megaraptorans), Fukuivenator (sometimes considered to be a basal therizinosaur), and Migmanychion . The results of his phylogenetic analysis are displayed in the cladogram below: [12]
Coelurosauria is the clade containing all theropod dinosaurs more closely related to birds than to carnosaurs.
Ceratosaurs are members of the clade Ceratosauria, a group of dinosaurs defined as all theropods sharing a more recent common ancestor with Ceratosaurus than with birds. The oldest known ceratosaur, Saltriovenator, dates to the earliest part of the Jurassic, around 199 million years ago. Ceratosauria includes three major clades: Ceratosauridae, Noasauridae, and Abelisauridae, found primarily in the Southern Hemisphere. Originally, Ceratosauria included the above dinosaurs plus the Late Triassic to Early Jurassic Coelophysoidea and Dilophosauridae, implying a much earlier divergence of ceratosaurs from other theropods. However, most recent studies have shown that coelophysoids and dilophosaurids do not form a natural group with other ceratosaurs, and are excluded from this group.
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, and coelurosaurs. 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.
Ornitholestes is a small theropod dinosaur of the late Jurassic of Western Laurasia.
Coelurus is a genus of coelurosaurian dinosaur from the Late Jurassic period. The name means "hollow tail", referring to its hollow tail vertebrae. Although its name is linked to one of the main divisions of theropods (Coelurosauria), it has historically been poorly understood, and sometimes confused with its better-known contemporary Ornitholestes. Like many dinosaurs studied in the early years of paleontology, it has had a confusing taxonomic history, with several species being named and later transferred to other genera or abandoned. Only one species is currently recognized as valid: the type species, C. fragilis, described by Othniel Charles Marsh in 1879. It is known from one partial skeleton found in the Morrison Formation of Wyoming, United States. It was a small bipedal carnivore with elongate legs.
Proceratosaurus is a genus of carnivorous theropod dinosaur from the Middle Jurassic (Bathonian) of England. It contains a single species. P. bradleyi, known from a mostly complete skull and lower jaws. Proceratosaurus was a small dinosaur, estimated to measure around 3 m (9.8 ft) in length. Its name refers to how it was originally thought to be an ancestor of Ceratosaurus, due to the partially preserved portion of the crest of Proceratosaurus superficially resembling the small crest of Ceratosaurus. Now, however, it is considered a coelurosaur, specifically a member of the family Proceratosauridae, and amongst the earliest known members of the clade Tyrannosauroidea.
Elaphrosaurus is a genus of ceratosaurian theropod dinosaur that lived approximately 154 to 150 million years ago during the Late Jurassic Period in what is now Tanzania in Africa. Elaphrosaurus was a medium-sized but lightly built member of the group that could grow up to 6.2 m (20 ft) long. Morphologically, this dinosaur is significant in two ways. Firstly, it has a relatively long body but is very shallow-chested for a theropod of its size. Secondly, it has very short hindlimbs in comparison with its body. Phylogenetic analyses indicate that this genus is likely a ceratosaur. Earlier suggestions that it is a late surviving coelophysoid have been examined but generally dismissed. Elaphrosaurus is currently believed to be a very close relative of Limusaurus, an unusual beaked ceratosaurian which may have been either herbivorous or omnivorous.
Siamotyrannus is a genus of theropod dinosaur from the early Cretaceous of Thailand.
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.
Tyrannosauroidea is a superfamily of coelurosaurian theropod dinosaurs that includes the family Tyrannosauridae as well as more basal relatives. Tyrannosauroids lived on the Laurasian supercontinent beginning in the Jurassic Period. By the end of the Cretaceous Period, tyrannosauroids were the dominant large predators in the Northern Hemisphere, culminating in the gigantic Tyrannosaurus. Fossils of tyrannosauroids have been recovered on what are now the continents of North America, Europe and Asia, with fragmentary remains possibly attributable to tyrannosaurs also known from South America and Australia.
Calamosaurus was a genus of small theropod dinosaur from the Barremian-age Lower Cretaceous Wessex Formation of the Isle of Wight, England. It is based on two cervical vertebrae, collected by Reverend William Fox.
Chuandongocoelurus is a genus of carnivorous tetanuran theropod dinosaur from the Jurassic of China.
Tanycolagreus is a genus of coelurosaurian theropod from the Late Jurassic of North America.
Thomas Richard Holtz Jr. is an American vertebrate palaeontologist, author, and principal lecturer at the University of Maryland's Department of Geology. He has published extensively on the phylogeny, morphology, ecomorphology, and locomotion of terrestrial predators, especially on tyrannosaurids and other theropod dinosaurs. He wrote the book Dinosaurs and is the author or co-author of the chapters "Saurischia", "Basal Tetanurae", and "Tyrannosauroidea" in the second edition of The Dinosauria. He has also been consulted as a scientific advisor for the Walking with Dinosaurs BBC series as well as the Discovery special When Dinosaurs Roamed America, and has appeared in numerous documentaries focused on prehistoric life, such as Jurassic Fight Club on History and Monsters Resurrected, Dinosaur Revolution and Clash of the Dinosaurs on Discovery.
Compsognathidae is a family of coelurosaurian theropod dinosaurs. Compsognathids were small carnivores, generally conservative in form, hailing from the Jurassic and Cretaceous Periods. The bird-like features of these species, along with other dinosaurs such as Archaeopteryx inspired the idea for the connection between dinosaur reptiles and modern-day avian species. Compsognathid fossils preserve diverse integument — skin impressions are known from four genera commonly placed in the group, Compsognathus, Sinosauropteryx, Sinocalliopteryx, and Juravenator. While the latter three show evidence of a covering of some of the earliest primitive feathers over much of the body, Juravenator and Compsognathus also show evidence of scales on the tail or hind legs. "Ubirajara jubatus", informally described in 2020, had elaborate integumentary structures on its back and shoulders superficially similar to the display feathers of a standardwing bird-of-paradise, and unlike any other non-avian dinosaur currently described.
The Shishugou Formation is a geological formation in Xinjiang, China.
Proceratosauridae is a family or clade of tyrannosauroid theropod dinosaurs from the Middle Jurassic to the Early Cretaceous.
Zuolong is an extinct genus of tetanuran theropod from the Late Jurassic period of China. The type and only species is Z. salleei. The generic name of Zuolong is in honor of General Zuo Zōngtáng with the Chinese word "long" which means dragon. The specific epithet "salleei" is in honor of Hilmar Sallee, who funded the expedition which led to the specimen's discovery.
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