Shanag Temporal range: Early Cretaceous, | |
---|---|
Reconstructed Skull | |
Scientific classification | |
Domain: | Eukaryota |
Kingdom: | Animalia |
Phylum: | Chordata |
Clade: | Dinosauria |
Clade: | Saurischia |
Clade: | Theropoda |
Clade: | Paraves |
Family: | † Dromaeosauridae |
Genus: | † Shanag Turner et al., 2007 |
Species: | †S. ashile |
Binomial name | |
†Shanag ashile Turner et al., 2007 | |
Shanag is a genus of paravian theropod dinosaur from the Early Cretaceous Period of Mongolia. It may be a dromaeosaurid, but some researchers are skeptical of this classification. The type species is S. ashile.
Shanag was named and described by Alan Turner, Sunny Hai-Ching Hwang and Mark Norell in 2007. The generic name refers to the black-hatted dancers in the Buddhist Cham dance. The specific name refers to the Ashile Formation, the old name for the layers where Shanag was found, used by Henry Fairfield Osborn. [1]
The holotype of Shanag, IGM 100/1119, was discovered in the Öösh Formation, the stratification of which is uncertain but probably dating to the Berriasian-Barremian. Shanag bears a strong resemblance to basal Chinese dromaeosaurids such as Microraptor and Sinornithosaurus , suggesting a close similarity between the fauna of the Öösh deposits, dated tentatively to 130 million years ago, and the Jehol Biota of China (such as the animals found in the roughly contemporary Yixian Formation), during the Early Cretaceous. [1]
Shanag was a small predator, measuring about 1.5 metres (4.9 ft) long and weighing around 5 kilograms (11 lb). [2] Shanag shows a mixture of dromaeosaurid, troodontid and basal avialan traits. [1]
The holotype specimen, about six centimeters long, is composed of an associated uncompressed upper and lower jaw fragment, containing a nearly complete right maxilla with teeth, a partial right dentary with teeth and an attached partial splenial. [1] The fossilized teeth in the specimen were pointed with serrations along the lengths of the posterior teeth, but no anterior teeth were available. [1] Shanag is autopomorphic as it lacks promaxillary fenestra and has interalveolar pneumatic cavities, which separates it from its nearest relative of S. millenii. [1] Its teeth have unusually long root lengths, making up about 70% of the overall tooth length. [1]
As part of the Theropoda group, Shanag had hollow bones and feathers. Though most were not capable of flight, some theropods used their feathers to assist in climbing or simply scrambling up tree trunks. [3] Feathers also allowed for thermoregulation by reducing the amount of airflow near the skin and preventing heat loss. [4] Their wings, though not capable of flight, could be used to stabilize themselves while on their prey via flapping like extant raptor birds. [5] Shanag are also believed to be endothermic based on their high speed and high level of activity. [3]
Sharp middle toe (D-II) claws of dromaeosaurs were initially thought to be for disemboweling prey, and then later tests suggested that due to the claw’s strength and cutting ability that they were used as a climbing tool for scaling the backs of prey larger than themselves. [6] This claim of scaling was later contested, and it was suggested the claws were used to grip and pin down prey similarly to extant birds of prey. [5]
In 2007, Turner and colleagues assigned Shanag to the Dromaeosauridae. Their cladistic analysis indicated that it was a basal dromaeosaurid but higher in the tree than the Unenlagiinae. [1] Later analyses recovered it in the Microraptorinae. [7] In 2012, Shanag was recovered as a sister taxon to the Unenlagiinae. [8] In 2013, Agnolín and Novas claimed that the traits of Shanag once used to identify the taxon as a dromaeosaurid closely related to the unenlagiines, were actually found in many other groups of paravian theropods such as the troodontids, avialans, and other basal paravians, with some features suggesting that it is more likely an avialan. Thus, they concluded that Shanag can only be identified as a basal averaptoran. [9]
A 2017 study still recovered Shanag as a dromaeosaurid based on phylogenetic analyses, but as a sister taxon to Laurasian dromaeosaurids from the Late Cretaceous and not related to unenlagiines. [10] In 2019, Agnolín and colleagues argued that Shanag cannot be confidently classified as a dromaeosaurid other than being a paravian. [11] In 2024, Porfiri and colleagues classified Shanag and Pyroraptor as sister taxa to unenlagiines, [12] while Wang and Pei recovered Shanag within Serraraptoria which includes microraptorians and eudromaeosaurians. [13]
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.
Dromaeosauridae is a family of feathered coelurosaurian theropod dinosaurs. They were generally small to medium-sized feathered carnivores that flourished in the Cretaceous Period. The name Dromaeosauridae means 'running lizards', from Greek δρομαῖος (dromaîos), meaning 'running at full speed', 'swift', and σαῦρος (saûros), meaning 'lizard'. In informal usage, they are often called raptors, a term popularized by the film Jurassic Park; several genera include the term "raptor" directly in their name, and popular culture has come to emphasize their bird-like appearance and speculated bird-like behavior.
Sinornithosaurus is a genus of feathered dromaeosaurid dinosaur from the early Cretaceous Period of the Yixian Formation in what is now China. It was the fifth non–avian feathered dinosaur genus discovered by 1999. The original specimen was collected from the Sihetun locality of western Liaoning. It was found in the Jianshangou beds of the Yixian Formation, dated to 124.5 million years ago. Additional specimens have been found in the younger Dawangzhangzi bed, dating to around 122 million years ago.
Buitreraptor is a genus of dromaeosaurid dinosaurs that lived during the Late Cretaceous of Argentina at the Candeleros Formation. Buitreraptor was described in 2005 and the type species is Buitreraptor gonzalezorum. It was rooster-sized and had a very elongated head with many small teeth.
Adasaurus is a genus of dromaeosaurid dinosaur that lived in Asia during the Late Cretaceous period about 70 million years ago. The genus is known from two partial specimens found in the Nemegt Formation of Mongolia that were partially described in 1983 by the paleontologist Rinchen Barsbold.
Jinfengopteryx is a genus of maniraptoran dinosaur. It was found in the Qiaotou Member of the Huajiying Formation of Hebei Province, China, and is therefore of uncertain age. The Qiaotou Member may correlate with the more well-known Early Cretaceous Yixian Formation, and so probably dates to around 122 Ma ago.
Microraptoria is a clade of basal dromaeosaurid theropod dinosaurs. Definitive microraptorians lived during the Barremian to Aptian stages of the Early Cretaceous in China. Many are known for long feathers on their legs and may have been semiarboreal powered fliers, some of which were even capable of launching from the ground. Most microraptorians were relatively small; adult specimens of Microraptor range between 77–90 centimetres long (2.53–2.95 ft) and weigh up to 1 kg (2.2 lb), making them some of the smallest known non-avialan dinosaurs.
Rahonavis is a genus of bird-like theropod from the Late Cretaceous of what is now northwestern Madagascar. It is known from a partial skeleton found by Catherine Forster and colleagues in Maevarano Formation rocks at a quarry near Berivotra, Mahajanga Province. Rahonavis was a small predator, at about 70 centimetres (2.3 ft) long and 0.45-2.27 kg, with the typical dromaesaurid-like raised sickle claw on the second toe. It was originally the first African coelurosaur until the discovery of Nqwebasaurus in 2000.
Pyroraptor is an extinct genus of paravian dinosaur, probably a dromaeosaurid or unenlagiid, from the Late Cretaceous Ibero-Armorican island, of what is now southern France. It lived during the late Campanian and early Maastrichtian stages, approximately 72 million years ago. It is known from a single partial specimen that was found in Provence in 1992, after a forest fire. The animal was named Pyroraptor olympius by Allain and Taquet in 2000.
Unenlagia is a genus of dromaeosaurid theropod dinosaur that lived in South America during the Late Cretaceous period. The genus Unenlagia has been assigned two species: U. comahuensis, the type species described by Novas and Puerta in 1997, and U. paynemili, described by Calvo et al. in 2004.
Unquillosaurus is a genus of large theropod dinosaur from the Late Cretaceous Los Blanquitos Formation of Salta Province, Argentina. Its precise classification is uncertain, but most researchers consider it as a maniraptoran. The genus contains a single species, U. ceibalii, known only from a single fossilized pubis.
Unenlagiinae is a subfamily of long-snouted paravian theropods. They are traditionally considered to be members of Dromaeosauridae, though some authors place them into their own family, Unenlagiidae, sometimes alongside the subfamily Halszkaraptorinae. Definitive members are known from South America, though some researchers include taxa from other continents within this subfamily based on phylogenetic analyses.
Paraves are a widespread group of theropod dinosaurs that originated in the Middle Jurassic period. In addition to the extinct dromaeosaurids, troodontids, anchiornithids, and possibly the scansoriopterygids, the group also contains the avialans, which include diverse extinct taxa as well as the over 10,000 species of living birds.
Austroraptor is a genus of dromaeosaurid theropod dinosaur that lived during the Campanian and Maastrichtian ages of the Late Cretaceous period in what is now Argentina.
Hesperonychus is a genus of small paravian theropod dinosaur. It may be a dromaeosaurid or an avialan. There is one described species, Hesperonychus elizabethae. The type species was named in honor of Dr. Elizabeth Nicholls of the Royal Tyrrell Museum of Palaeontology who collected it as a student in 1982. It is known from fossils recovered from the Dinosaur Park Formation and possibly from the uppermost strata of the Oldman Formation of Alberta, dating to the Campanian stage of the Late Cretaceous around 75 million years ago.
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.
Eudromaeosauria is a subgroup of terrestrial dromaeosaurid theropod dinosaurs. They were small to large-sized predators that flourished during the Cretaceous Period. Eudromaeosaur fossils are known almost exclusively from the northern hemisphere.
Pamparaptor is an extinct genus of paravian theropod dinosaur from the Late Cretaceous Portezuelo Formation of the Neuquén province in Argentine Patagonia. Its precise classification is uncertain, but the authors who described this taxon have argued that it is a dromaeosaurid. The genus contains a single species, P. micros, which is known from a single specimen consisting of a mostly complete and fully-articulated left foot, which preserves the iconic dromaeosaur-like "killing claw".
This timeline of dromaeosaurid research is a chronological listing of events in the history of paleontology focused on the dromaeosaurids, a group of sickle-clawed, bird-like theropod dinosaurs including animals like Velociraptor. Since the Native Americans of Montana used the sediments of the Cloverly Formation to produce pigments, they may have encountered remains of the dromaeosaurid Deinonychus hundreds of years before these fossils came to the attention of formally trained scientists.
Overoraptor is an extinct genus of paravian theropod of uncertain affinities from the Late Cretaceous Huincul Formation of Argentinian Patagonia. The genus contains a single species, O. chimentoi, known from several bones of the hands, feet, and hips alongside some vertebrae.