''Urbacodon'' ("URBAC tooth") is a

genus Genus ( plural genera ) is a taxonomic rank used in the biological classification of extant taxon, living and fossil organisms as well as Virus classification#ICTV classification, viruses. In the hierarchy of biological classification, genus com ...

of troodontid

dinosaur Dinosaurs are a diverse group of reptiles of the clade Dinosauria. They first appeared during the Triassic period, between 243 and 233.23 million years ago (mya), although the exact origin and timing of the evolution of dinosaurs is t ...

, a type of small carnivore. It lived in

Uzbekistan Uzbekistan (, ; uz, Ozbekiston, italic=yes / , ; russian: Узбекистан), officially the Republic of Uzbekistan ( uz, Ozbekiston Respublikasi, italic=yes / ; russian: Республика Узбекистан), is a doubly landlocked cou ...

during the early

Late Cretaceous The Late Cretaceous (100.5–66 Ma) is the younger of two epochs into which the Cretaceous Period is divided in the geologic time scale. Rock strata from this epoch form the Upper Cretaceous Series. The Cretaceous is named after ''creta'', the ...

Period, about 95 million years ago. On 9 September 2004, a lower jaw of a small theropod was uncovered by Anton Sergeevich Rezwiy near Itemir in the IT-01 quarry. The

type species In zoological nomenclature, a type species (''species typica'') is the species name with which the name of a genus or subgenus is considered to be permanently taxonomically associated, i.e., the species that contains the biological type specimen ...

, ''Urbacodon itemirensis'', was named by Alexandr Averianov and

Hans-Dieter Sues Hans-Dieter Sues (born January 13, 1956) is a German-born American paleontologist who is Senior Scientist and Curator of Vertebrate Paleontology at the National Museum of Natural History of the Smithsonian Institution in Washington, DC. He receiv ...

2007 File:2007 Events Collage.png, From top left, clockwise: Steve Jobs unveils Apple's first iPhone; TAM Airlines Flight 3054 overruns a runway and crashes into a gas station, killing almost 200 people; Former Pakistani Prime Minister of Pakistan, Pr ...

. The first part of the generic name ''Urbacodon'' is an

acronym An acronym is a word or name formed from the initial components of a longer name or phrase. Acronyms are usually formed from the initial letters of words, as in ''NATO'' (''North Atlantic Treaty Organization''), but sometimes use syllables, as ...

, 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 Specific name may refer to: * in Database management systems, a system-assigned name that is unique within a particular database In taxonomy, either of these two meanings, each with its own set of rules: * Specific name (botany), the two-part (bino ...

refers to the provenance from Itemir. The name was based on the

holotype A holotype is a single physical example (or illustration) of an organism, known to have been used when the species (or lower-ranked taxon) was formally described. It is either the single such physical example (or illustration) or one of several ...

ZIN PH 944/16, a single left dentary with preserved replacement teeth from the

Cenomanian The Cenomanian is, in the ICS' geological timescale, the oldest or earliest age of the Late Cretaceous Epoch or the lowest stage of the Upper Cretaceous Series. An age is a unit of geochronology; it is a unit of time; the stage is a unit in the s ...

Dzharakuduk Formation. Averianov and Sues also identified teeth and other material, earlier described by

Lev Nesov Lev may refer to: Common uses * Bulgarian lev, the currency of Bulgaria *an abbreviation for Leviticus, the third book of the Hebrew Bible and the Torah People and fictional characters * Lev (given name) *Lev (surname) Places *Lev, Azerbaijan, ...

, as a ''Urbacodon'' sp. from the nearby

Turonian The Turonian is, in the ICS' geologic timescale, the second age in the Late Cretaceous Epoch, or a stage in the Upper Cretaceous Series. It spans the time between 93.9 ± 0.8 Ma and 89.8 ± 1 Ma (million years ago). The Turonian is preceded by t ...

Bissekty Formation. The holotype dentary of ''U. itemirensis'' is 79.2 millimetres long (3.12 in) 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 A diastema (plural diastemata, from Greek διάστημα, space) is a space or gap between two teeth. Many species of mammals have diastemata as a normal feature, most commonly between the incisors and molars. More colloquially, the condition ...

. This is a unique trait but was not formally designated as an

autapomorphy In phylogenetics, an autapomorphy is a distinctive feature, known as a derived trait, that is unique to a given taxon. That is, it is found only in one taxon, but not found in any others or outgroup taxa, not even those most closely related to t ...

because it might be the result of individual variation. ''Urbacodon'' resembles ''

Byronosaurus ''Byronosaurus'' is a genus of troodontid dinosaur from the Late Cretaceous Period of Mongolia. Discovery and naming In 1993, Michael Novacek, a member of an American Museum of Natural History expedition to the Gobi Desert, discovered the skele ...

'' and ''

Mei Mei may refer to: Names * Mei (surname), a Chinese, Italian, Russian or Estonian family name * Mei (given name), a given name Places * Mei County, Guangdong, China, a county * Mei Pass, Guangdong, a strategic mountain pass * Mei River, Guangdong ...

'' 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. Averianov and Sues viewed ''Urbacodon'' as more

plesiomorphic In phylogenetics, a plesiomorphy ("near form") and symplesiomorphy are synonyms for an ancestral character shared by all members of a clade, which does not distinguish the clade from other clades. Plesiomorphy, symplesiomorphy, apomorphy, and ...

than '' Troodon'' and ''

Saurornithoides ''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 deriv ...

'' in having a straight dentary with fewer teeth, but did not attempt to place it on a cladogram. In 2010, a cladistic analysis showed it as a close relative of ''

'' and '' Xixiasaurus''.Lü J.-C, Xu L., Liu Y.-Q., Zhang X.-L., Jia S. & Ji Q., 2010, "A new troodontid (Theropoda: Troodontidae) from the Late Cretaceous of central China, and the radiation of Asian troodontids", ''Acta Palaeontologica Polonica'' 55(3): 381-388

References

{{Taxonbar, from=Q1950821 Troodontids Turonian life Late Cretaceous dinosaurs of Asia Fossils of Uzbekistan Bissekty Formation Fossil taxa described in 2007 Taxa named by Hans-Dieter Sues

See also

References