Utahraptor (meaning "Utah's predator" or "Utah's thief") is a genus of theropod dinosaurs. It contains a single species, Utahraptor ostrommaysorum, which is the largest-known member of the family Dromaeosauridae. Fossil specimens date to the upper Barremian stage of the early Cretaceous period (in rock strata dated to 126 ± 2.5 million years ago).
In 2018, it was proposed that Utahraptor be the Utah state dinosaur, an act that was approved by the Senate. Initially Utahraptor would have replaced another dinosaur, Allosaurus, as the state's official fossil, but it was decided that Utahraptor would be another symbol of the state.
Kirkland, Gaston & Burge, 1993
Kirkland et al, 1993
The holotype specimen of Utahraptor is fragmentary, consisting of skull fragments, a tibia, claws and some caudal (tail) vertebrae. These few elements suggest an animal about twice the length of Deinonychus. Like other dromaeosaurids, Utahraptor had large curved claws on their second toes. One claw specimen is preserved at 22 centimeters (8.7 in) in length and is thought to reach 24 cm (9.4 in) restored.
The largest described U. ostrommaysorum specimens are estimated to have reached up to 7 meters (23 ft) long and somewhat less than 500 kilograms (1,100 lb) in weight, comparable to a grizzly bear or polar bear in size. However, the 2001 Kirkland discovery indicates the species may be far heavier than previously estimated.
It is thought that Utahraptor is closely related to the smaller Dromaeosaurus and the giant Mongolian and North American dromaeosaurid genera Achillobator and Dakotaraptor, based on cladistic analysis.
Although feathers have never been found in association with Utahraptor specimens, there is strong phylogenetic evidence suggesting that all dromaeosaurids possessed them. This evidence comes from phylogenetic bracketing, which allows paleontologists to infer traits that exist in a clade based on the existence of that trait in a more basal form. The genus Microraptor is one of the oldest-known dromaeosaurids, and is phylogenetically more primitive than Utahraptor. Since Microraptor and other dromaeosaurids possessed feathers, it is reasonable to assume that this trait was present in all of Dromaeosauridae. Feathers were very unlikely to have evolved more than once, so assuming that any given dromaeosaurid, such as Utahraptor, lacked feathers would require positive evidence that they did not have them. So far, there is nothing to suggest that feathers were lost in larger, more derived species of dromaeosaurs.
The first specimens of Utahraptor were found in 1975 by Jim Jensen in the Dalton Wells Quarry in east-central Utah, near the town of Moab, but did not receive much attention. After a find of a large foot-claw by Carl Limoni in October 1991, James Kirkland, Robert Gaston, and Donald Burge uncovered further remains of Utahraptor in 1991 in the Gaston Quarry in Grand County, Utah, within the Yellow Cat and Poison Strip members of the Cedar Mountain Formation. Radiometric dating has shown that these parts of the Cedar Mountain Formation were deposited about 124 million years ago. The type specimen, CEU 184v.86, is currently housed at the College of Eastern Utah Prehistoric Museum, although Brigham Young University, the depository of Jensen's finds, currently houses the largest collection of Utahraptor fossils.
The type species (and only known species of Utahraptor), Utahraptor ostrommaysorum, was named by Kirkland, Gaston, and Burge in June 1993 for the American paleontologist John Ostrom from Yale University's Peabody Museum of Natural History, and Chris Mays of Dinamation International. Earlier, it had been intended to name the species "Utahraptor spielbergi" after film director Steven Spielberg, in exchange for funding paleontological research, but no agreement could be reached on the amount of financial assistance.
In 2001, Kirkland et al, pursued a graduate student's discovery of a bone protruding from a 9-ton fossil block of sandstone in eastern Utah. It was determined to contain the bones of at least seven individuals, including an adult measuring about 4.8 m (16 ft), four juveniles and a hatchling about 1 m (3.3 ft) long. Also fossilized with the predators are the remains of at least one possible iguanodont herbivore.
Kirkland speculated that the Utahraptors attempted to scavenge carrion or attack helpless prey mired in quicksand, and were themselves mired in the attempt to attack the herbivore. Similar sites such as the Cleveland-Lloyd Quarry and California's La Brea Tar Pits house such predator traps. Examination of the fossils are ongoing after a decade of excavation, but if Kirkland is correct, it may be one of the best preserved predator traps ever discovered. The fossils may further reveal aspects into the behavior of Utahraptor, such as whether it might have hunted in groups like Deinonychus is believed to have done. Whether all the Utahraptor individuals were mired simultaneously or were drawn in, one-by-one, is unclear, as work is currently slowed on the specimens. More concrete answers may yet come to light once crowdfunding efforts to employ professional excavator, Utahraptor Project leader Scott Madsen, are completed.
Utahraptor is a member of the family Dromaeosauridae, a clade of theropod dinosaurs commonly known as "raptors". Utahraptor is the largest genus in the family, and belongs to the same clade as some famous dinosaurs such as Velociraptor, Deinonychus or Dromaeosaurus. Utahraptor is classified in the subfamily Dromaeosaurinae, which is found in the clade Eudromaeosauria.
Below is a cladogram by Senter et al. in 2012.
According to the authors of its description, Utahraptor had an important ecological role as a major carnivore of the fauna of the present-day Arks region in the early Cretaceous", and could probably attack prey larger than itself. Group hunting of individuals of at least 3.5 m and 70 kg, if proven, could have killed 8 m prey of a weight of one to two tonnes. According to paleontologist Gregory S. Paul, Utahraptor was not particularly fast and would have been an ambush hunter that preyed on large dinosaurs such as the contemporary iguanodontians and therizinosauroids it shared its environment with. Its robust build and large sickle claw indicates it was well suited to hunting such prey. Like other dromaeosaurine dromaeosaurids, it may have also relied heavily on its jaws to dispatch prey—more so than other types of dromaeosaurids, such as velociraptorines.
Utahraptor lived in the lower part of the Cedar Mountain Formation, which during the Barremian was a semiarid area with floodplain prairies, riverine forests, and open woodlands. There is believed to have been a short wet season. Other fauna that were contemporaneous with the dromaeosaurid in the Yellow Cat and Poison Strip Members included the therizinosauroids Falcarius and Martharaptor, the sauropods Cedarosaurus, Mierasaurus, Venenosaurus and Moabosaurus, the iguanodonts Iguanacolossus, Planicoxa, Cedrorestes and Hippodraco, and the ankylosaur Gastonia. Fellow dromaeosaurid Yurgovuchia, the troodontid Geminiraptor and the ornithomimosaur Nedcolbertia also dwelled here. Birds, fish, mammals such as Cifelliodon, turtles, crocodiles, and pterosaurs are also known from the formation, creating a diverse fauna.
Raptor Red was published in 1995, and features the fictionalized story of a female Utahraptor. Written by paleontologist Robert T. Bakker, it was positively regarded by mainstream reviewers, though updates to the science have rendered some of the story line facts presented untrue and the paleontology community was critical of fossil record inaccuracies. Bakker's anthropomorphisis of the titular Red was particularly praised.
Achillobator ( ə-KIL-ə-BAY-tor) is a dromaeosaurid theropod dinosaur that lived roughly 93 to 80 million years ago during the Late Cretaceous in what is now Mongolia, in Asia. It was among the largest dromaeosaurs; the holotype and only known individual of Achillobator is estimated at 5 to 6 m (16.4 to 19.7 ft) long. Achillobator was a moderately-built, ground-dwelling, bipedal carnivore. It would have been an active predator, hunting with the enlarged, sickle-shaped claw on the second toe.Adasaurus
Adasaurus ( AH-də-SAWR-əs; "Ada's lizard") is a dromaeosaurid theropod dinosaur from the Late Cretaceous Period of Central Asia. It was a small bipedal carnivore with a sickle-shaped claw on the second toe of each hind foot, and was perhaps 1.8 m (5.9 ft) long. The genus name Adasaurus is taken from Ada, an evil spirit in the mythology of Mongolia, and the Greek word sauros meaning 'lizard'. The species name, for the single species, (A. mongoliensis), refers to the country of origin. Adasaurus was named and described in 1983 by Mongolian paleontologist Rinchen Barsbold.
Adasaurus is a member of Dromaeosauridae, a group that is closely related to living birds. Other dromaeosaurids include Deinonychus, Velociraptor, Microraptor, and Buitreraptor. The relationships of Adasaurus are poorly understood. Traditionally, Adasaurus is assigned to the Dromaeosaurinae, which includes heavily built animals such as Dromaeosaurus and Utahraptor but several recent studies have suggested that it may be a member of the Velociraptorinae instead.Two specimens of Adasaurus have been found, both from the Nemegt Formation in the Gobi Desert of southern Mongolia. The holotype, IGM 100/20, is an incomplete skeleton with partial skull, including the vertebral column except the back of the tail, all three bones of the pelvis, the shoulder girdle and the hindlimbs. The second specimen, the paratype IGM 100/51 also described in the original paper, consists of the back end of another skeleton, including the hindlimbs. Both specimens are currently in the collection of the Mongolian Geological Institute in Ulaanbaatar, Mongolia.
The age of the Nemegt is not known for certain, but it is commonly thought to belong to the Maastrichtian stage of the Late Cretaceous Period., and Adasaurus would therefore have lived between 72 and 66 million years ago. Other dinosaurs found in this formation include the tyrannosaur Tarbosaurus, the ornithomimid Anserimimus, the troodontid Zanabazar, and the hadrosaur Saurolophus.Austroraptor
Austroraptor ( AW-stroh-RAP-tər) is an extinct genus of dromaeosaurid dinosaur that lived about 70 million years ago during the Cretaceous Period in what is now modern Argentina. Austroraptor was a medium sized, moderately-built, ground-dwelling, bipedal carnivore, that could grow up to 5–6 m (16.4–19.7 ft) long. Its length makes Austroraptor one of the largest dromaeosaurids known, with only Achillobator, Dakotaraptor, and Utahraptor approaching or surpassing it in length. It is the largest dromaeosaur to be discovered in the Southern Hemisphere. Particularly notable about the taxon were its relatively short forearms, much shorter in proportion when compared to the majority of the members of its group.Barremian
The Barremian is an age in the geologic timescale (or a chronostratigraphic stage) between 129.4 ± 1.5 Ma (million years ago) and 125.0 ± 1.0 Ma). It is a subdivision of the Early Cretaceous epoch (or Lower Cretaceous series). It is preceded by the Hauterivian and followed by the Aptian stage.Dakotaraptor
Dakotaraptor is a genus of large carnivorous dromaeosaurid theropod from the Late Cretaceous of North America.
The first fossils of Dakotaraptor were found in South Dakota, United States, in 2005. In 2015, the genus Dakotaraptor received its name, meaning "plunderer of Dakota", when the type species Dakotaraptor steini was described. The fossils contain an incomplete skeleton without a skull and some individual bones. They have been found in the Maastrichtian-age Hell Creek Formation, dated to the very end of the Cretaceous period, making Dakotaraptor one of the last surviving dromaeosaurids.
Dakotaraptor was about 5.5 metres (18 ft) long, which makes it one of the largest dromaeosaurids known. It had long arms with one of the lower arm bones showing quill knobs, demonstrating that it was most likely feathered. It also had long rear legs with a very large sickle claw on the second toe; this claw could be used to kill relatively large plant-eating dinosaurs. It lived in the same time and area as many iconic late Cretaceous dinosaurs such as Ankylosaurus, Triceratops, and Tyrannosaurus.Dinosaur Comics
Dinosaur Comics is a constrained webcomic by Canadian writer Ryan North. It is also known as "Qwantz", after the site's domain name, "qwantz.com". The first comic was posted on February 1, 2003, although there were earlier prototypes. Dinosaur Comics has also been printed in three collections and in a number of newspapers. The comic centers on three main characters, T-Rex, Utahraptor and Dromiceiomimus.Comics are posted every Monday, Wednesday, and Friday. Every strip uses the same artwork and panel layout; only the dialogue changes from day to day. There are occasional deviations from this principle, including a number of episodic comics. North created the comic because it was something he'd "long wanted to do but couldn’t figure out how to accomplish... [he doesn't] draw, so working in a visual medium like comics isn’t the easiest thing to stumble into."Dromaeosauridae
Dromaeosauridae is a family of feathered 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 δρομεῦς (dromeus) meaning 'runner' and σαῦρος (sauros) meaning 'lizard'. In informal usage they are often called raptors (after Velociraptor), a term popularized by the film Jurassic Park; a few types include the term "raptor" directly in their name and have come to emphasize their bird-like appearance and speculated bird-like behavior.
Dromaeosaurid fossils have been found across the globe in North America, Europe, Africa, Asia, South America and Antarctica, with fossilized teeth giving credence to the possibility that they inhabited Australia as well. They first appeared in the mid-Jurassic Period (late Bathonian stage, about 167 million years ago) and survived until the end of the Cretaceous (Maastrichtian stage, 66 ma), existing until the Cretaceous–Paleogene extinction event. The presence of dromaeosaurids as early as the Middle Jurassic has been suggested by the discovery of isolated fossil teeth, though no dromaeosaurid body fossils have been found from this period.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).Dromaeosaurus
Dromaeosaurus (, "swift running lizard") is a genus of theropod dinosaur which lived during the Late Cretaceous period (middle late Campanian), sometime between 76.5 and 74.8 million years ago, in the western United States and Alberta, Canada. The type species is Dromaeosaurus albertensis, which was described by William Diller Matthew and Barnum Brown in 1922.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.Imperobator
Imperobator ("powerful warrior") is a genus of paravian theropod that lived during the Late Cretaceous period in what is now Antarctica. It contains a single species, I. antarcticus, recovered from the Snow Hill Island Formation. Before its description, it was informally nicknamed the "Naze dromaeosaur", despite the lack of a "sickle claw" characteristic of the group. In 2019, the describing authors suggested that Imperobator had the same size as Utahraptor.Itemirus
Itemirus is a genus of theropod dinosaur from the Turonian age of the Late Cretaceous period of Uzbekistan.James I. Kirkland
James Ian Kirkland (born August 24, 1954) is an American paleontologist and geologist. He has worked with dinosaur remains from the south west United States of America and Mexico and has been responsible for discovering new and important genera. He named (or worked with others in naming) Animantarx, Cedarpelta, Eohadrosaurus (nomen nudum, now named Eolambia), Jeyawati, Gastonia, Mymoorapelta, Nedcolbertia, Utahraptor, Zuniceratops, Europelta and Diabloceratops. At the same site where he found Gastonia and Utahraptor, Kirkland has also excavated fossils of the therizinosaurs Nothronychus and Falcarius.John Radcliffe Hospital
The John Radcliffe Hospital is a large tertiary teaching hospital in Oxford, England and a leading centre for medical research. It is the main teaching hospital for Oxford University and Oxford Brookes University, and incorporates the Oxford University Medical School. It forms part of the Oxford University Hospitals NHS Foundation Trust and is named after John Radcliffe, an 18th-century physician and Oxford University graduate, who endowed the Radcliffe Infirmary, the main hospital for Oxford from 1770 until 1979.Jurassic Fight Club
Jurassic Fight Club (titled Dinosaur Secrets in Australia/UK) is a paleontology-based television series on History channel which premiered in the US in July 2008. Jurassic Fight Club was hosted by George Blasing, a self-taught paleontologist, and also features well-known paleontologists such as Thomas R. Holtz Jr., Lawrence Witmer, Phillip J. Currie, and others. The show ran for one season of 12 episodes and was not renewed.List of U.S. state dinosaurs
This is a list of U.S. state dinosaurs in the United States, including the District of Columbia. A large number of states also have dinosaurs as state fossils, but this list only includes those that have been officially designated as "state dinosaurs". All U.S. states also have a state bird, the direct evolutionary descendants of dinosaurs.Raptor Red
Raptor Red is a 1995 American novel by paleontologist Robert T. Bakker. The book is a third-person account of dinosaurs during the Cretaceous Period, told from the point of view of Raptor Red, a female Utahraptor. Raptor Red features many of Bakker's theories regarding dinosaurs' social habits, intelligence, and the world in which they lived.
The book follows a year in Raptor Red's life as she loses her mate, finds her family, and struggles to survive in a hostile environment. Bakker drew inspiration from Ernest Thompson Seton's works that look at life through the eyes of predators, and said that he found it "fun" to write from a top predator's perspective. Bakker based his portrayals of dinosaurs and other prehistoric wildlife on fossil evidence, as well as studies of modern animals.
When released, Raptor Red was generally praised: Bakker's anthropomorphism was seen as a unique and positive aspect of the book, and his writing was described as folksy and heartfelt. Criticisms of the novel included a perceived lack of characterization and average writing. Some scientists, such as paleontologist David B. Norman, took issue with the scientific theories portrayed in the novel, fearing that the public would accept them as fact, while Discovery Channel host Jay Ingram defended Bakker's creative decisions in an editorial.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.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.