''Khulsanurus'' (meaning "tail from Khulsan") is an extinct genus of

alvarezsaurid Alvarezsauridae is a family of small, long-legged dinosaurs. Although originally thought to represent the earliest known flightless birds, they are now thought to be an early diverging branch of maniraptoran theropods. Alvarezsaurids were highly ...

theropod Theropoda (; from ancient Greek , (''therion'') "wild beast"; , (''pous, podos'') "foot"">wiktionary:ποδός"> (''pous, podos'') "foot" is one of the three major groups (clades) of dinosaurs, alongside Ornithischia and Sauropodom ...

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

from the

Late Cretaceous The Late Cretaceous (100.5–66 Ma) is the more recent 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 ''cre ...

Barungoyot Formation of the Khulsan Locality in the

Gobi Desert The Gobi Desert (, , ; ) is a large, cold desert and grassland region in North China and southern Mongolia. It is the sixth-largest desert in the world. The name of the desert comes from the Mongolian word ''gobi'', used to refer to all of th ...

region of

Mongolia Mongolia is a landlocked country in East Asia, bordered by Russia to the north and China to the south and southeast. It covers an area of , with a population of 3.5 million, making it the world's List of countries and dependencies by po ...

. The type and only species is ''Khulsanurus magnificus''.

Description

''Khulsanurus'' is known from a

holotype A holotype (Latin: ''holotypus'') is a single physical example (or illustration) of an organism used when the species (or lower-ranked taxon) was formally described. It is either the single such physical example (or illustration) or one of s ...

containing partial vertebral series of the neck and tail, scapulocoracoids, a right humerus, a possible left humerus, and a left pubis. Distinguishing autapomorphies of this specimen include pleurocoel-, carotid process-, and epipophysis-less cervical vertebrae, prominent infrapostzygapophyseal fossa of the caudal vertebrae which also bear anteriorly pointing prezygapophyses.

Classification

Averianov & Lopatin (2021) placed ''Khulsanurus'' in a

polytomy An internal node of a phylogenetic tree is described as a polytomy or multifurcation if (i) it is in a rooted tree and is linked to three or more child subtrees or (ii) it is in an unrooted tree and is attached to four or more branches. A tree ...

with ''

Albinykus ''Albinykus'' (meaning " Albin claw", after a term used by Mongolian shamans to describe light phenomena in the Gobi Desert) is a genus of alvarezsaurid dinosaur. Fossils have been found from Late Cretaceous-age (Santonian) Javkhlant Formation i ...

'', ''

Ceratonykus ''Ceratonykus'' (meaning "horned claw") is a monospecific genus of alvarezsaurid dinosaur from Mongolia that lived during the Late Cretaceous (late Campanian stage, 72.1 Ma) in what is now the Barun Goyot Formation. The type and only species, ''C ...

'', ''

Linhenykus ''Linhenykus'' is an extinct genus of alvarezsaurid theropod dinosaur from the Late Cretaceous of Inner Mongolia, China. It is the most basal known member of the Parvicursorinae. The genus gets its name from Linhe, a city near the site where t ...

'', ''

Parvicursor ''Parvicursor'' (meaning "small runner") is a genus of tiny maniraptoran dinosaur with long slender legs for fast running. Discovery and naming The holotype PIN no. 4487/25, mostly consisting of vertebrae, the pelvis and the right hindlimb, w ...

'', ''

Xixianykus ''Xixianykus'' is a genus of alvarezsaurid theropod dinosaur from the late Cretaceous period of China. Known from a slab of rock which contains a partial postcranial skeleton unearthed in the Late Cretaceous ( Coniacian-Santonian) Majiacun For ...

'', ''

Qiupanykus ''Qiupanykus'' (IPA: , meaning "claw from the Qiupa Formation") is an extinct genus of alvarezsaurid theropod from the Late Cretaceous Qiupa Formation of Henan Province, China. The type and only species is ''Q. zhangi'', named for Shuancheng Zh ...

'', ''

Nemegtonykus ''Nemegtonykus'' (meaning "Nemegt claw" after the Nemegt Formation where it was found) is a genus of alvarezsaurid dinosaur from the Nemegt Formation in Mongolia. The type species, type and only species is ''Nemegtonykus citus''. It is the second ...

'', PIN 5838/1 (=''

Ondogurvel ''Ondogurvel'' (meaning "egg lizard") is a genus of alvarezsaurid dinosaur from the Late Cretaceous (Campanian) Barun Goyot Formation in southern Mongolia. The type and only species is ''O. alifanovi'', known from a partial skeleton consisting of ...

'') and a clade containing ''

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 ...

'' and ''

Mononykus ''Mononykus'' ( , sometimes ; meaning "one claw") is a genus of alvarezsaurid dinosaur that lived during the Late Cretaceous in what is now Asia on the Nemegt Formation, about 70 million years ago. ''Mononykus'' was a very small theropod, estim ...

'' in a strict consensus tree using unweighted characters. However, Averianov & Lopatin (2021) also recovered it in a polytomy with only ''Albinykus'', ''Xixianykus'', PIN 5838/1 (=''Ondogurvel''), ''Mononykus'' and ''Shuvuuia'' in a consensus tree using implied weighting. Averianov & Sues (2022) conducted a phylogenetic analysis using implied weighting which recovered it in a similar position but with inclusion of a clade containing ''Linhenykus'', ''Ceratonykus'' and ''Parvicuror'' and the exclusion of ''Qiupanykus'' and ''Nemegtonykus'', while a 50% majority rule tree from the same analysis placed it within a polytomy with two clades. A phylogenetic analysis conducted by Averianov & Sues (2022) is reproduced below.

Paleoenvironment

''Khulsanurus'' was found in the Campanian

Barun Goyot Formation The Baruungoyot Formation (also known as Barun Goyot) is a geological formation dating to the Late Cretaceous Period. It is located within and is widely represented in the Gobi Desert Basin, in the Ömnögovi Province of Mongolia. Descriptio ...

, which was also home to many other animals, including mammals such as ''

Catopsbaatar ''Catopsbaatar'' is a genus of multituberculate, an extinct Order (biology), order of rodent-like mammals. It lived in what is now Mongolia during the late Campanian age of the Late Cretaceous epoch (geology), epoch, about 72 million years ...

'' and ''

Nemegtbaatar ''Nemegtbaatar'' is an extinct genus of mammal from the Upper Cretaceous Period of what is now Central Asia. It belonged to the order Multituberculata. ''Nemegtbaatar'' is within the suborder Cimolodonta and is a member of the superfamily Dja ...

'', squamates such as ''

Estesia ''Estesia'' (in honour of Richard Estes) is an extinct genus of Late Cretaceous anguimorph lizard found in the Gobi Desert in Mongolia. Discovery It was discovered in June 1990 by a joint expedition made up of Mongolian and American palaeon ...

'', ''

Gobiderma ''Gobiderma'' is an extinct genus of Late Cretaceous lizard whose fossils are known from the Gobi Desert in southern Mongolia. It was first discovered as a result of a joint Polish-Mongolian Paleontological Expedition, and formally named in 1984 ...

'', and '' Proplatynotia'', and numerous dinosaurs, including ornithischians such as ''

Saichania ''Saichania'' (Mongolian meaning "beautiful one") is a genus of herbivorous ankylosaurid dinosaur from the Late Cretaceous period of Mongolia. The first fossils of ''Saichania'' were found in the early 1970s in Mongolia. In 1977 the type speci ...

'', ''

Tarchia ''Tarchia'' (meaning "brainy one") is a genus of herbivorous ankylosauridae, ankylosaurid dinosaur from the late Cretaceous of Mongolia. Discovery and naming In 1970, a Polish-Mongolian expedition discovered an ankylosaurian skull near Khulsan. ...

'', '' Zaraapelta'', '' Tylocephale'', ''

Bagaceratops ''Bagaceratops'' (meaning "small-horned face") is a genus of small protoceratopsid dinosaurs that lived in Asia during the Late Cretaceous, around 72 to 71 million years ago. ''Bagaceratops'' remains have been reported from the Barun Goyot Forma ...

'', ''

Breviceratops ''Breviceratops'' (meaning "short horned face") is a genus of protoceratopsid dinosaur that lived during the Late Cretaceous in what is now the Barun Goyot Formation, Mongolia. Discovery and naming The first fossils were discovered during the 1 ...

'', and ''

Udanoceratops ''Udanoceratops'' (meaning "Udan's horned face") is a genus of large leptoceratopsid dinosaur that lived during the Late Cretaceous Period (geology), period of Mongolia. Discovery ''Udanoceratops'' was first named and described by Russian paleo ...

''; sauropods such as '' Quaesitosaurus'';Kurzanov, S. and Bannikov, A. (1983). "A new sauropod from the Upper Cretaceous of Mongolia". ''Paleontologicheskii Zhurnal'' 2: 90–96. and theropods, including ''

Conchoraptor ''Conchoraptor'' (meaning "conch plunderer") is a genus of oviraptorid dinosaurs that lived in Asia during the Late Cretaceous epoch, about 70 million years ago. It is known from the Barun Goyot and Nemegt Formation, Nemegt formations of Mongolia ...

'', ''

Heyuannia ''Heyuannia'' ("from Heyuan") is a genus of oviraptorid dinosaur that lived in Asia during the Late Cretaceous epoch, in what is now China and Mongolia. It was the first oviraptorid found in China; most others were found in neighbouring Mongolia ...

'', ''

Nemegtomaia ''Nemegtomaia'' is a genus of oviraptorid dinosaur from what is now Mongolia that lived in the Late Cretaceous Period (geology), Period, about 70million years ago. The first specimen was found in 1996, and became the basis of the new genus and s ...

'', '' Hulsanpes'', '' Kuru'', ''

Shri Shri (; , ) is a Sanskrit term denoting resplendence, wealth and prosperity, primarily used as an honorific. The word is widely used in South and Southeast Asian languages such as Assamese, Meitei ( Manipuri), Marathi, Malay (including In ...

'', ''

Gobipteryx ''Gobipteryx'' (from Gobi eferring to the Gobi Desert where it was first discovered and Greek pteryx "wing") is a genus of prehistoric bird from the Campanian Age of the Late Cretaceous Period.Elżanowski, A. (1974)"Preliminary note on the Pala ...

'', and '' Hollanda''.

References

{{Taxonbar, from=Q109642447 Alvarezsauridae Dinosaur genera Maastrichtian dinosaurs Baruungoyot Formation Dinosaurs of Mongolia Fossil taxa described in 2022 Taxa named by Alexander O. Averianov