''Kol'' (from the Mongolian хөл/''köl'', meaning "foot") is an extinct

genus Genus ( plural genera ) is a taxonomic rank used in the biological classification of living and fossil organisms as well as viruses. In the hierarchy of biological classification, genus comes above species and below family. In binomial nom ...

of coelurosaurian

theropod Theropoda (; ), whose members are known as theropods, is a dinosaur clade that is characterized by hollow bones and three toes and claws on each limb. Theropods are generally classed as a group of saurischian dinosaurs. They were ancestrally c ...

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 ...

from the

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'', ...

Mongolia Mongolia; Mongolian script: , , ; lit. "Mongol Nation" or "State of Mongolia" () is a landlocked country in East Asia, bordered by Russia to the north and China to the south. It covers an area of , with a population of just 3.3 million, ...

. The type and only species is ''Kol ghuva'' (from the Mongolian гува/''ghuv-a'', meaning "beautiful"). The

type specimen In biology, a type is a particular specimen (or in some cases a group of specimens) of an organism to which the scientific name of that organism is formally attached. In other words, a type is an example that serves to anchor or centralizes th ...

was excavated from the Ukhaa Tolgod locality of the

Djadochta Formation The Djadochta Formation (sometimes Transcription (linguistics), transcribed and also known as Djadokhta, Djadokata, or Dzhadokhtskaya) is a highly fossiliferous geological formation situated in Central Asia, Gobi Desert, dating from the Late Creta ...

, dating to about 75 million years ago. It is believed to have been about twice the size of the contemporary ''

Shuvuuia ''Shuvuuia'' is a genus of bird-like theropod dinosaur from the late Cretaceous period of Mongolia. It is a member of the family Alvarezsauridae, small coelurosaurian dinosaurs which are characterized by short but powerful forelimbs specialized f ...

''. However, unlike ''Shuvuuia'', which is known from many well preserved specimens, and although Ukhaa Tolgod has been thoroughly explored, ''Kol'' is known only from one complete foot, suggesting that it must have been relatively rare in that ecosystem. Because of the incomplete nature of the type specimen (catalog number IGM 100/2011), the exact relationship of ''Kol'' to other coelurosaurs has been difficult to determine. However, ''Kol'' shows an extreme arctometatarsalian condition of the foot bones, in which the middle metatarsal is severely pinched between the outer bones (usually considered an adaptation for fast running, also seen in ornithomimosaurs and

tyrannosaurs Tyrannosauroidea (meaning 'tyrant lizard forms') is a superfamily (or clade) of coelurosaurian theropod dinosaurs that includes the family Tyrannosauridae as well as more basal relatives. Tyrannosauroids lived on the Laurasian supercontinent ...

). It has been estimated at in length and in body mass, making it one of the largest members of the group. Some studies have instead recovered ''Kol'' outside the Alvarezsauridae, more closely related to ''

Avimimus ''Avimimus'' ( ), meaning "bird mimic" (Latin ''avis'' = bird + ''mimus'' = mimic), is a genus of oviraptorosaurian theropod dinosaur, named for its bird-like characteristics, that lived in the late Cretaceous in what is now Mongolia, around 85 ...

'' within the

Oviraptorosauria Oviraptorosaurs ("egg thief lizards") are a group of feathered maniraptoran dinosaurs from the Cretaceous Period of what are now Asia and North America. They are distinct for their characteristically short, beaked, parrot-like skulls, with or wi ...

, and a recent study of Mongolian alvarezsaurids excluded ''Kol'' from the Alvarezsauridae.

References

Late Cretaceous dinosaurs of Asia Djadochta fauna Fossil taxa described in 2009 {{theropod-stub Prehistoric maniraptorans