Boreonykus

Boreonykus is an extinct genus of dromaeosaurid dinosaur, that lived during the Late Cretaceous in the area of present Canada.[1]

Fragmentary dromaeosaurid remains were discovered in the eighties at the Pipestone Creek site in central Alberta during excavations of a bonebed containing at least twenty-seven individuals of the ceratopsid Pachyrhinosaurus lakustai.[1] They were initially partly referred to a Saurornitholestes sp.[2]

The type species Boreonykus certekorum was named and described by Phil Bell and Philip John Currie in 2015.[1] The genus name is a variation of "Boreonychus", "northern claw". The specific name certekorum honors the Certek Heating Solutions company, that works in the oil industry, and provided financial support for the excavations.[1]

The holotype specimen of Boreonykus, TMP 1989.055.0047, was found in a layer of the Wapiti Formation in central Alberta, which dates from the late Campanian, 73.27 ± 0.25 million years ago. It consists of a right frontal bone. Fourteen loose teeth have been referred to the species, as well as several postcranial bones, perhaps of the same individual: the specimen TMP 1988.055.0129, a rear caudal vertebra; UALVP 53597, a claw of the second finger, and the specimen TMP 1986.055.0184.1, a sicle claw of the foot.[1]

A single autapomorphy, unique derived trait, was indicated: the ridges bordering the fronts of the depressions around the supratemporal fenestrae form an acute angle of 55° together, pointing to the rear.[1]

Boreonykus was, within the Dromaeosauridae, placed in the Velociraptorinae. It was seen as both an indication of faunal provincialism and a quick species turn-over rate.[1]

Boreonykus
Temporal range: Late Cretaceous 73 Ma
Scientific classification
Kingdom: Animalia
Phylum: Chordata
Clade: Dinosauria
Order: Saurischia
Suborder: Theropoda
Family: Dromaeosauridae
Subfamily: Velociraptorinae
Genus: Boreonykus
Bell & Currie, 2015
Type species
Boreonykus certekorum
Bell & Currie, 2015

References

  1. ^ a b c d e f g Bell, P. R., and P. J. Currie. 2015. A high-latitude dromaeosaurid, Boreonykus certekorum, gen. et sp. nov. (Theropoda), from the upper Campanian Wapiti Formation, west-central Alberta. Journal of Vertebrate Paleontology. DOI: 10.1080/02724634.2015.1034359.
  2. ^ Ryan M.J. and Russell, A.P., 2001, "The dinosaurs of Alberta (exclusive of Aves)", In: Tanke and Carpenter (eds.), Mesozoic Vertebrate Life: New Research Inspired by the Paleontology of Philip J. Currie, Indiana University Press, pp 279-297
Dromaeosaurinae

Dromaeosaurinae is a subfamily of Dromaeosauridae. Most dromaeosaurines lived in what is now the United States and Canada, as well as Mongolia, and possibly Denmark as well. Isolated teeth that may belong to African dromaeosaurines have also been discovered in Ethiopia. These teeth date to the Tithonian stage, of the Late Jurassic Period.All North American and Asian dromaeosaurine dinosaurs from the Late Cretaceous were generally small, no more than 1.8 metres (5.9 ft) long, in Dromaeosaurus and Adasaurus. However, among the dromaeosaurines were the largest dromaeosaurs ever; Dakotaraptor was ~5.5 metres (18 ft) long, Achillobator 6 metres (20 ft), and Utahraptor up to ~7 metres (23 ft).

Eudromaeosauria

Eudromaeosauria ("true dromaeosaurs") is a subgroup of terrestrial dromaeosaurid theropod dinosaurs. They were relatively large-bodied, feathered hypercarnivores (with diets consisting almost entirely of other terrestrial vertebrates) that flourished in the Cretaceous Period.

Eudromaeosaur fossils are known almost exclusively from the northern hemisphere. They first appeared in the early Cretaceous Period (early Aptian stage, about 124 million years ago) and survived until the end of the Cretaceous (Maastrichtian stage, 66 Ma). The earliest known definitive eudromaeosaur is the dromaeosaurine Utahraptor ostrommaysorum, from the Cedar Mountain Formation, dated to 124 million years ago. However, the earlier (143-million-year-old) fossils such as those of Nuthetes destructor and several indeterminate teeth dating to the Kimmeridgian stage may represent eudromaeosaurs.

Graciliraptor

Graciliraptor (meaning "graceful thief") is a genus of theropod dinosaur from the early Cretaceous Period. It is a microraptorine dromaeosaurid.

The type species Graciliraptor lujiatunensis was first named and described in 2004 by Xu Xing and Wang Xiaoling. The generic name is derived from Latin gracilis and raptor. The specific name refers to the village Lujiatun where the fossil site is located. Its fossil, holotype IVPP V 13474, was found in Beipiao, Liaoning Province, China.

Halszkaraptorinae

Halszkaraptorinae is a basal ("primitive") subfamily of Dromaeosauridae that includes the enigmatic genera Halszkaraptor, Mahakala, and Hulsanpes. A comparison of the fossils of Halszkaraptor with the bones of extant crocodilians and aquatic birds revealed evidence of a semiaquatic lifestyle. The group is named after Polish paleontologist Halszka Osmólska.

Hulsanpes

Hulsanpes is a genus of dromaeosaurid theropod dinosaur from Mongolia that lived during the Late Cretaceous.

Itemirus

Itemirus is a genus of theropod dinosaur from the Turonian age of the Late Cretaceous period of Uzbekistan.

Linheraptor

Linheraptor is a genus of dromaeosaurid dinosaur which lived in what is now China in the Late Cretaceous. It was named by Xu Xing and colleagues in 2010, and contains the species Linheraptor exquisitus. This bird-like dinosaur was less than 2 m (6.5 ft) long and was found in Inner Mongolia. It is known from a single, nearly complete skeleton.

Luanchuanraptor

Luanchuanraptor (meaning "Luanchuan thief") is a genus of dromaeosaurid theropod dinosaur from the Late Cretaceous of China. It is based on a partial skeleton from the Qiupa Formation in Luanchuan, Henan. A medium-sized dromaeosaurid, it is the first Asian dromaeosaurid described from outside the Gobi Desert or northeastern China. The fossil material is cataloged as 4HIII-0100 in the Henan Geological Museum and includes four teeth, one frontal, a neck vertebra, one or two back vertebrae, seventeen tail vertebrae, ribs, chevrons, a humerus (upper arm bone), claw and finger bones, partial shoulder and pelvic girdles, and other fragmentary bones from a moderately sized dromaeosaurid. The type species is L. henanensis, described by Lü et al. in 2007.

Pamparaptor

Pamparaptor is an extinct genus of carnivorous deinonychosaur from the late Cretaceous period. It is a basal dromaeosaurid dinosaur with troodontid-like pes which lived during the late Cretaceous period (Turonian to Coniacian stage) in what is now Neuquén province, Patagonia, Argentina. It is known from the holotype MUCPv-1163, an articulated and nearly complete left foot.

The specimen recovered from the Portezuelo Formation (Río Neuquén Subgroup) of Neuquén Group. It was initially considered to be a juvenile specimen of another dromaeosaurid species, Neuquenraptor argentinus. However, it was later re-interpreted as a new genus and named Pamparaptor by Juan D. Porfiri, Jorge O. Calvo and Domenica dos Santos in 2011 and the type species is Pamparaptor micros. The generic name honors Indian Pampas people who lived in central Argentina while "raptor" (robber in Latin). The specific name (micros, meaning "small") refers to the specimen's size (estimated at 0.5 to 0.7 metres (1.6 to 2.3 ft) in length).

Pyroraptor

Pyroraptor (meaning "fire thief") is a genus of dromaeosaurid dinosaur from the Late Cretaceous of what is now southern France, it lived during the late Campanian and early Maastrichtian stages, approximately 70.6 million years ago. It is known from a single partial specimen that was found in Provence in 1992. The animal was named Pyroraptor olympius by Allain and Taquet in 2000.

Saurornitholestinae

Saurornitholestinae is a subfamily of dromaeosaurid dinosaurs. The saurornitholestines currently include three monotypic genera: Atrociraptor marshalli, Bambiraptor feinbergorum, and Saurornitholestes langstoni. All are medium-sized dromaeosaurs from the Late Cretaceous of western North America. The group was originally recognized by Longrich and Currie as the sister taxon to a clade formed by the Dromaeosaurinae and Velociraptorinae. However, not all phylogenetic analyses recover this group.

Shanag

Shanag is a genus of dromaeosaurid theropod dinosaur from the Early Cretaceous Period of Mongolia.

The type species of Shanag is S. ashile. It 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.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. The holotype specimen, about six centimetres 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.Shanag was a small predator. In 2010 Gregory S. Paul estimated its length at 1.5 metres, the weight at five kilogrammes. Shanag shows a mixture of dromaeosaurid, troodontid and basal avialan traits.Turner et alii assigned Shanag to the Dromaeosauridae. Their cladistic analysis indicated that it was a basal dromaeosaurid but higher in the tree than the Unenlagiinae. Later analyses recovered it in the Microraptorinae.

Unenlagiinae

Unenlagiinae is a subfamily of dromaeosaurid theropods. Unenlagiines are known from South America and Antarctica.

Unquillosaurus

Unquillosaurus (meaning "Unquillo river lizard") is a genus of maniraptoran dinosaur from the Late Cretaceous Period, discovered in Argentina. Known only from a single fossilized pubis (a pelvic bone), its total body length may have reached 2 to 3 metres (6.6 to 9.8 ft).

Variraptor

Variraptor ( VARR-i-rap-tor; "Var thief") is a genus of coelurosaurian theropod dinosaur from the Late Cretaceous of France.

Velociraptorinae

Velociraptorinae is a subfamily of the theropod group Dromaeosauridae. The earliest velociraptorines are probably Nuthetes from the United Kingdom, and possibly Deinonychus from North America. However, several indeterminate velociraptorines have also been discovered, dating to the Kimmeridgian stage, in the Late Jurassic Period. These fossils were discovered in the Langenberg quarry, Oker near Goslar, Germany.In 2007 paleontologists studied front limb bones of Velociraptor and discovered small bumps on the surface, known as quill knobs. The same feature is present in some bird bones, and represents the attachment point for strong secondary wing feathers. This finding provided the first direct evidence that velociraptorines, like all other maniraptorans, had feathers.While most velociraptorines were generally small animals, at least one species may have achieved gigantic sizes comparable to those found among the dromaeosaurines. So far, this unnamed giant velociraptorine is known only from isolated teeth found on the Isle of Wight, England. The teeth belong to an animal the size of dromaeosaurines of the genus Utahraptor, but they appear to belong to a velociraptorine, judging by the shape of the teeth and the anatomy of their serrations.

Wapiti Formation

The Wapiti Formation is a geological formation of the Western Canada Sedimentary Basin in northwestern Alberta, and Northeastern British Columbia, Canada. Its deposition spanned the time interval from Late Cretaceous (Campanian stage) to early Paleocene, and it includes sediments that were deposited before, during, and after the Cretaceous-Paleogene (K-Pg) extinction event. It was named by G.M. Dawson in 1881, presumably for exposures along the lower part of the Wapiti River and downstream along the Smoky River in Alberta.Dinosaur remains are among the fossils that have been recovered from the Cretaceous portion of the formation. The Wapiti Formation does not produce many fossils due to its limited surface exposure and accessibility, although two Pachyrhinosaurus bone beds have been productive.

Yurgovuchia

Yurgovuchia is an extinct genus of dromaeosaurid theropod dinosaur known from the Early Cretaceous (probably Barremian stage) of Utah. It contains a single species, Yurgovuchia doellingi. According to a phylogenetic analysis performed by its describers, it represents an advanced dromaeosaurine, closely related to Achillobator, Dromaeosaurus and Utahraptor.

Zhongjianosaurus

Zhongjianosaurus is a genus of dromaeosaurid belonging to the Microraptoria. Believed to hail from the Yixian Formation, specifically the middle of the Jehol Biota, it is the smallest known microraptorine thus far discovered and one of the smallest non-avian theropod dinosaurs.

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