| Xiyunykus | |
|---|---|
 | |
| Scaled reconstruction | |
Scientific classification  | |
| Kingdom: | Animalia |
| Phylum: | Chordata |
| Clade: | Dinosauria |
| Clade: | Saurischia |
| Clade: | Theropoda |
| Clade: | † Alvarezsauria |
| Genus: | † Xiyunykus Xu et al., 2018 |
| Type species | |
| †Xiyunykus pengi Xu et al., 2018 | |
Xiyunykus (meaning "western claw"; "xiyu" is Mandarin for "west" and refers to Western China where it was found [1] ) is an alvarezsaur from the Early Cretaceous of the Tugulu Group of China. It includes one species, Xiyunykus pengi. [1]
Dinosaurs contemporaneous with Xiyunykus in the Tugulu Group of Xinjiang include the stegosaur Wuerhosaurus , the coeval alvarezsaur Tugulusaurus , the carcharodontosaurid Kelmayisaurus , the dubious maniraptoran Phaedrolosaurus , the problematic coelurosaur Xinjiangovenator , and the ceratopsian Psittacosaurus xinjiangensis .[ citation needed ]
Xiyunykus, along with Bannykus , fills a 70-million year gap in alvarezsaur evolution by exhibiting cranial and postcranial morphologies intermediate between the typical theropod forelimb of Haplocheirus and the highly reduced forelimbs and minute teeth of Late Cretaceous alvarezsaurids.[ citation needed ]
Theropoda, whose members are known as theropods, is a dinosaur clade that is characterized by hollow bones and three-toed limbs. Theropods are generally classed as a group of saurischian dinosaurs. They were ancestrally carnivorous, although a number of theropod groups evolved to become herbivores, omnivores, piscivores, and insectivores. Theropods first appeared during the Carnian age of the late Triassic period 231.4 million years ago (Ma) and included the sole large terrestrial carnivores from the Early Jurassic until at least the close of the Cretaceous, about 66 Ma. In the Jurassic, birds evolved from small specialized coelurosaurian theropods, and are today represented by about 10,500 living species.
Alvarezsauridae is a family of small, long-legged dinosaurs. Although originally thought to represent the earliest known flightless birds, a consensus of recent work suggests that they evolved from an early branch of maniraptoran theropods. Alvarezsaurids were highly specialized. They had tiny but stout forelimbs, with compact, bird-like hands. Their skeletons suggest that they had massive breast and arm muscles, possibly adapted for digging or tearing. They had long, tube-shaped snouts filled with tiny teeth. They may have been adapted to prey on colonial insects such as termites.
Maniraptora is a clade of coelurosaurian dinosaurs which includes the birds and the non-avian dinosaurs that were more closely related to them than to Ornithomimus velox. It contains the major subgroups Avialae, Deinonychosauria, Oviraptorosauria and Therizinosauria. Ornitholestes and the Alvarezsauroidea are also often included. Together with the next closest sister group, the Ornithomimosauria, Maniraptora comprises the more inclusive clade Maniraptoriformes. Maniraptorans first appear in the fossil record during the Jurassic Period, and are regarded as surviving today as living birds.
Mei is a genus of duck-sized troodontid dinosaur first unearthed by paleontologists from the Yixian Formation in Liaoning, China in 2004. Mei lived during the Early Cretaceous period. The binomial name of its only species, Mei long, means sleeping dragon.
Yixianosaurus is a maniraptoran theropod dinosaur genus from the Early Cretaceous of China.
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, Asia, South America and Australia.
Tugulusaurus is a genus of coelurosaurian theropod dinosaur that possibly belongs to the Alvarezsauria. It is known from the Early Cretaceous Tugulu Group in the Urhe area of the People's Republic of China.
Sinovenator is a genus of troodontid dinosaur from China. It is from the early Cretaceous Period.
Kelmayisaurus is an extinct genus of carcharodontosaurid theropod dinosaur from the Early Cretaceous. It was roughly 10–12 meters long and its name refers to the petroleum-producing city of Karamay in the Xinjiang province of western China near where it was found.
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 found in the Iren Dabasu Formation; it was only slightly larger than the contemporaneous giant oviraptorid Gigantoraptor.
The Tugulu Group is a geological Group in Xinjiang, China whose strata date back to the Early Cretaceous. Dinosaur remains are among the fossils that have been recovered from the formation.
The Bayin-Gobi Formation or Bayingebi Formation is a geological formation in Inner Mongolia, north China, whose strata date back to Albian of the Early Cretaceous period.
Tianyuraptor is a genus of short-armed dromaeosaurid dinosaur that lived during the Early Cretaceous, about 122 million years ago. Its remains have been found in western Liaoning, China. It was similar to other dromaeosaurids found in Liaoning, with the exception of being somewhat more primitive. The type specimen, formally named in 2009, shows features not seen in previously known Northern Hemisphere (Laurasian) dromaeosaurids, but present in Southern Hemisphere (Gondwanan) species and early birds. Because of this, the scientists who first studied Tianyuraptor described it as a "transitional species", bridging the gap between northern and southern types of dromaeosaurid. Tianyuraptor also differs from previously known dromaeosaurids in that it possesses a relatively small furcula ("wishbone"), and unusually short forelimbs.
Alvarezsauroidea is a group of small maniraptoran dinosaurs. Alvarezsauroidea, Alvarezsauridae, and Alvarezsauria are named for the historian Gregorio Álvarez, not the more familiar physicist Luis Alvarez, who proposed that the Cretaceous–Paleogene extinction event was caused by an impact event. The group was first formally proposed by Choiniere and colleagues in 2010, to contain the family Alvarezsauridae and non-alvarezsaurid alvarezsauroids, such as Haplocheirus, which is the basalmost of the Alvarezsauroidea. The discovery of Haplocheirus extended the stratigraphic evidence for the group Alvarezsauroidea about 63 million years further in the past. The division of Alvarezsauroidea into the Alvarezsauridae and the non-alvarezsaurid alvarezsauroids is based on differences in their morphology, especially in their hand morphology.
Shantungosuchus is an extinct genus of Early Cretaceous crocodyliform found in China. It includes three species: Shantungosuchus chuhsienensis and S. brachycephalus, which were both described by Yang Zhongjian – usually referred to as "Young" – in 1961 and 1982, and S. hangjinensis, which was described by Xiao-Chun Wu et al in 1994. S. chuhsienensis is the type for this genus.
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 the fossil was first found and Greek nykus, "claw". The specific name is derived from Greek monos, "single", and daktylos, "finger", a reference to the fact that it is the only known non-avian dinosaur to have had but a single digit.
Linhevenator is a genus of short-armed troodontid theropod dinosaur from the Late Cretaceous (Campanian) Bayan Mandahu Formation of Bayan Mandahu, Inner Mongolia, China.
Aorun (pron.:"AW-roon") is an extinct genus of carnivorous theropod dinosaur first discovered in 2006, with its scientific description published in 2013. It is one of the oldest known coelurosaurian dinosaurs and is estimated to have lived ~161.6 million years ago during the Late Jurassic Period. It is the fifth theropod discovered from Wucaiwan.
Anchiornithidae is a family of eumaniraptorans which could be the basalmost family of birds in the clade Avialae. Anchiornithids have been classified at varying positions in the maniraptoran tree, with some scientists classifying them as a distinct family, a basal subfamily of Troodontidae, members of Archaeopterygidae, or an assemblage of dinosaurs that are an evolutionary grade within Avialae or Paraves.
Bannykus is an alvarezsaur from the Early Cretaceous of the Bayin-Gobi Formation of Inner Mongolia, China. It includes one species, Bannykus wulatensis. It is large for an alvarezsaur, with an estimated weight of 24 kg based on femoral circumference.
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