Urbacodon Temporal range: Late Cretaceous, | |
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Scientific classification ![]() | |
Domain: | Eukaryota |
Kingdom: | Animalia |
Phylum: | Chordata |
Clade: | Dinosauria |
Clade: | Saurischia |
Clade: | Theropoda |
Family: | † Troodontidae |
Subfamily: | † Troodontinae |
Genus: | † Urbacodon Averianov & Sues, 2007 |
Type species | |
Urbacodon itemirensis Averianov & Sues, 2007 | |
Other species | |
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Urbacodon (meaning "URBAC tooth") is a genus of troodontid theropod dinosaur. Two species have been described, both of which are known from a partial dentary: U. itemirensis from the Dzharakuduk Formation (Cenomanian) of Uzbekistan and U. norelli from the Iren Dabasu Formation of China. Possible remains are also known from the Bissekty Formation (Turonian) of Uzbekistan.
On 9 September 2004, a lower jaw of a small theropod was uncovered by Anton Sergeevich Rezwiy near Itemir in the IT-01 quarry. [1]
The type species, Urbacodon itemirensis, was named by Alexandr Averianov and Hans-Dieter Sues in 2007. The first part of the generic name Urbacodon is an acronym, honouring the Uzbek, Russian, British, American and Canadian scientists who participated in its discovery. This acronym was combined with a Greek ὀδών, odon, "tooth". The specific name refers to the provenance from Itemir. [1]
The name was based on the holotype ZIN PH 944/16, a single left dentary with preserved replacement teeth from the Cenomanian Dzharakuduk Formation. Averianov and Sues also identified teeth and other material, earlier described by Lev Nesov, as a Urbacodon sp. from the nearby Turonian Bissekty Formation. [1]
In 2024, Wang et al. described a partial right dentary collected from the Iren Dabasu Formation in the late 1990s. Based on similarities with U. itemirensis, they described the specimen as belonging to a new species of Urbacodon, which they named U. norelli. The two specimens share a lightly built and strap-like dentary that is curved inward at the tip, a symphyseal foramen on the dentary, and thickened dentary teeth, among other features. [2]
The holotype dentary of U. itemirensis is 79.2 millimetres (3.12 in) long and has 32 tooth positions. It is rather straight in top view. The teeth are closely packed but between the front twenty-four teeth and the rear eight teeth, a distinctive gap is present, a diastema. This is a unique trait but was not formally designated as an autapomorphy because it might be the result of individual variation. Urbacodon resembles Byronosaurus and Mei but differs from most other Troodontidae in that its teeth lack serrations. Urbacodon is distinguished from Byronosaurus by a less vascularized lateral dentary groove and more bulbous anterior tooth crowns, and from Mei by considerably larger size. [1]
Averianov and Sues viewed Urbacodon itemirensis as more plesiomorphic than Troodon and Saurornithoides in having a straight dentary with fewer teeth, but did not attempt to place it on a cladogram. [1] In 2010, a cladistic analysis showed it as a close relative of Byronosaurus and Xixiasaurus . [3]
In their description of Urbacodon norelli, Wang et al. (2024) discussed the phylogenetic position of both species. They recovered Zanabazar as the sister taxon to Urbacodon as late-diverging members of the Troodontidae. Their results are displayed in the cladogram below: [2]
Troodontidae |
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Troodontidae is a clade of bird-like theropod dinosaurs from the Late Jurassic to Late Cretaceous. During most of the 20th century, troodontid fossils were few and incomplete and they have therefore been allied, at various times, with many dinosaurian lineages. More recent fossil discoveries of complete and articulated specimens, have helped to increase understanding about this group. Anatomical studies, particularly studies of the most primitive troodontids, like Sinovenator, demonstrate striking anatomical similarities with Archaeopteryx and primitive dromaeosaurids, and demonstrate that they are relatives comprising a clade called Paraves.
Saurornitholestes is a genus of carnivorous dromaeosaurid theropod dinosaur from the late Cretaceous of Canada (Alberta) and the United States.
Saurornithoides is a genus of troodontid maniraptoran dinosaur, which lived during the Late Cretaceous period. These creatures were predators, which could run fast on their hind legs and had excellent sight and hearing. The name is derived from the Greek stems saur~ (lizard), ornith~ (bird) and eides (form), referring to its bird-like skull.
Alectrosaurus is a genus of tyrannosauroid theropod dinosaur that lived in Asia during the Late Cretaceous period, about some 96 million years ago in what is now the Iren Dabasu Formation.
Byronosaurus is a genus of troodontid dinosaur from the Late Cretaceous Period of Mongolia.
Archaeornithomimus is a genus of ornithomimosaurian theropod dinosaur that lived in Asia during the Late Cretaceous period, around 96 million years ago in the Iren Dabasu Formation.
Pectinodon is a genus of troodontid theropod dinosaurs from the end of the Maastrichtian age of the Late Cretaceous period (66 mya). It currently contains a single valid species, Pectinodon bakkeri, known only from teeth.
Itemirus is a genus of dromaeosaurid theropod dinosaur from the Turonian age of the Late Cretaceous period of Uzbekistan.
Erliansaurus is a genus of therizinosaur theropod dinosaur that lived in Asia during the Cenomanian stage of the Late Cretaceous period in what is now Nei Mongol, Iren Dabasu Formation.
Neimongosaurus is a genus of herbivorous therizinosaur theropod dinosaur that lived in Asia during the Cenomanian stage of the Late Cretaceous period in what is now the Iren Dabasu Formation.
Sonidosaurus is a genus of sauropod dinosaur from the Late Cretaceous. It was a titanosaur which lived in what is now Inner Mongolia. The type species, Sonidosaurus saihangaobiensis, was described by Xu, Zhang, Tan, Zhao, and Tan in 2006. It was a small titanosaur, about 9 meters (30 ft) long. It was first discovered in the Saihangaobi, Iren Dabasu (Erlian) Formation, in 2001 in a quarry which would later yield the remains of Gigantoraptor.
Gigantoraptor is a genus of large oviraptorosaur dinosaur that lived in Asia during the Late Cretaceous period. It is known from the Iren Dabasu Formation of Inner Mongolia, where the first remains were found in 2005.
The Iren Dabasu Formation is a Late Cretaceous geologic formation in the Iren Nor region of Inner Mongolia. Dinosaur remains diagnostic to the genus level are among the fossils that have been recovered from the formation. The formation was first described and defined by Henry Fairfield Osborn in 1922 and it is located in the Iren Nor region of China.
The Bissekty Formation is a geologic formation and Lagerstätte which crops out in the Kyzyl Kum desert of Uzbekistan, and dates to the Late Cretaceous Period. Laid down in the mid to late Turonian, it is dated to about 92 to 90 Ma.
Xixiasaurus is a genus of troodontid dinosaur that lived during the Late Cretaceous Period in what is now China. The only known specimen was discovered in Xixia County, Henan Province, in central China, and became the holotype of the new genus and species Xixiasaurus henanensis in 2010. The names refer to the areas of discovery, and can be translated as "Henan Xixia lizard". The specimen consists of an almost complete skull, part of the lower jaw, and teeth, as well as a partial right forelimb.
Linhevenator is a genus of short-armed troodontid theropod dinosaur from the Late Cretaceous (Campanian) Bayan Mandahu Formation of Bayan Mandahu, Inner Mongolia, China.
Talos is an extinct genus of carnivorous bird-like theropod dinosaur, an advanced troodontid which lived during the late Cretaceous period in the geographic area that is now Utah, United States.
This timeline of troodontid research is a chronological listing of events in the history of paleontology focused on the troodontids, a group of bird-like theropod dinosaurs including animals like Troodon. Troodontid remains were among the first dinosaur fossils to be reported from North America after paleontologists began performing research on the continent, specifically the genus Troodon itself. Since the type specimen of this genus was only a tooth and Troodon teeth are unusually similar to those of the unrelated thick-headed pachycephalosaurs, Troodon and its relatives would be embroiled in taxonomic confusion for over a century. Troodon was finally recognized as distinct from the pachycephalosaurs by Phil Currie in 1987. By that time many other species now recognized as troodontid had been discovered but had been classified in the family Saurornithoididae. Since these families were the same but the Troodontidae named first, it carries scientific legitimacy.
Kansaignathus is an extinct genus of dromaeosaurid theropod from the Late Cretaceous Yalovach Formation of Tajikistan. The genus contains only one species, the type species, K. sogdianus. The generic name of Kansaignathus comes from near the town of Konsoy where it was discovered and the Greek word "gnathos" meaning "jaw". The specific epithet "sogdianus" is derived from the historical region of Sogdiana, which was an ancient name for the Fergana Valley region where the fossil was discovered. Kansaignathus is known from a single right dentary bone and a few post-cranial bone fragments. It was the first, and so far the only, dinosaur from Tajikistan to be described and named.
Dzharaonyx is a genus of alvarezsaurid theropod dinosaur from the Late Cretaceous Bissekty Formation of Uzbekistan. The type species is Dzharaonyx eski; eski being an Uzbek word for "old".