User:Sheep81/Sandbox

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iHeterodontosauridae
Scientific classification
Kingdom: Animalia Phylum: Chordata Class: Sauropsida Superorder: Dinosauria Order: Ornithischia (unranked) Heterodontosauriformes Family: Heterodontosauridae Romer, 1966
Genera
Heterodontosaurus (type genus) Abrictosaurus Echinodon Lycorhinus

Heterodontosauridae ("different-toothed lizards") is a family of early ornithischian dinosaurs which were found around the globe from the Late Triassic Period to at least the Early Cretaceous. Heterodontosaurids fossils are rare and characterized mainly by features of their teeth, especially the enlarged canine-like teeth found in both upper and lower jaws. They are often considered basal ornithopods but recent studies suggest they may be more closely related to marginocephalians.

Contents 1 Anatomy 2 Lifestyle 3 Taxonomy and systematics 3.1 Classification 3.2 Phylogeny 4 Evolution 5 References 6 History 6.1 Discoveries 6.2 Manospondylus controversy 7 The world of Tyrannosaurus 8 Paleobiology 8.1 Size 8.2 Growth Rate 8.3 Posture 8.4 Feathers 8.5 Arms 8.6 Bite Force 8.7 Intelligence and senses 8.8 Speed 8.9 Feeding strategy 9 Appearances in popular culture 10 References 11 External Links

[edit] Anatomy

Among heterodontosaurids, only Heterodontosaurus itself is known from a complete skeleton. Fragmentary skeletal remains of Abrictosaurus are known but have not been fully described, while all other heterodontosaurids are known only from jaw fragments and teeth.

Heterodontosaurids are named for their strongly heterodont dentition. In both Heterodontosaurus and Abrictosaurus, the front of the premaxilla was toothless and probably covered by a rhamphotheca or beak. The rear of the premaxilla contained three teeth, the first two of which were small and conical, while the last was enlongated and resembled the canine teeth of mammals. This third tooth is commonly called the caniniform or tusk. A gap (known as a diastema) separated the premaxillary teeth from those of the maxilla. The lower jaw was tipped by the predentary, a bone unique to ornithischians. The predentary was toothless and probably also covered with a keratinous beak similar to the one on the premaxilla. The first dentary tooth of the lower jaw was also a caniniform which fit into the diastema of the upper jaw when the mouth closed. The lower caniniform was larger than the upper in both Abrictosaurus and Heterodontosaurus

[edit] Lifestyle

[edit] Taxonomy and systematics

[edit] Classification

[edit] Phylogeny

[edit] Evolution

[edit] References

named by Alfred Romer in 1966 to place Heterodontosaurus in. Such species as Echinodon and Pisanosaurus have been included. However Pisanosaurus is now no longer considered a heterodontosaurid, but a more basal ornithischian. Earlier seen as the sisterclade of Euornithopoda within Ornithopoda, they are today seen as a likely sistergroup of Marginocephalia, as indicated by the recent discovery of Yinlong.

The clade was defined in 1998 by Paul Sereno and redefined by him in 2005 as the stem clade consisting of Heterodontosaurus tucki and all species more closely related to Heterodontosaurus than to Parasaurolophus walkeri, Pachycephalosaurus wyomingensis, Triceratops horridus or Ankylosaurus magniventris.

The Heterodontosauridae ranged in time from the early till, if Echinodon is a heterodontosaurid, the late Jurassic period. Of all well known Heterodontosauridae individuals have been found that are heterodontomorphic, i.e. they have teeth of several clearly distinguishable types, which is uncommon for dinosaurs; i.c. the canines are strongly developed, perhaps an expression of sexual dimorphism.

[edit] History

Henry Fairfield Osborn, president of the American Museum of Natural History, named Tyrannosaurus rex in 1905. The generic name is derived from the Greek words τυραννος (tyrannos, meaning "tyrant") and σαυρος (sauros, meaning "lizard"). Osborn used the Latin word rex, meaning "king", for the specific name. The full binomial therefore translates to "tyrant lizard king," emphasizing the animal's size and perceived dominance over other species of the time.^[1]

[edit] Discoveries

Tyrannosaurus rex discoveries are restricted to North America. The holotype of Tyrannosaurus rex, a partial skull and skeleton originally called AMNH 973, was discovered in the U.S. state of Montana in 1902 and excavated over the next three years. Another specimen (AMNH 5866), found in Wyoming in 1900, was described in the same paper under the name Dynamosaurus imperiosus. At the time of their initial description and naming, these specimens had not been fully prepared and the type specimen of T. rex had not even been fully recovered.^[1] In 1906, after further preparation and examination, Osborn recognized both skeletons as belonging to the same species. Because the name Tyrannosaurus rex had appeared just one page earlier than Dynamosaurus in Osborn's 1905 work, it was considered the older name and has been used since. Had it not been for page order, Dynamosaurus would have become the official name.^[2]

Both of these specimens, as well as the hindlimbs of a third specimen (AMNH 5881), were collected by Barnum Brown, assistant curator of the American Museum of Natural History and a famous paleontologist in his own right. Brown also discovered the first complete skull of Tyrannosaurus rex, part of another specimen (AMNH 5027) located in Montana in 1907. In total, Brown found five partial Tyrannosaurus skeletons. Osborn planned to mount the similarly-sized AMNH 5027 and AMNH 973 together in dynamic poses as if they were fighting over a carcass.^[3] However, technical difficulties prevented the mount from being executed, and following the 1941 entry of the United States into World War II, the holotype was sold to the Carnegie Museum of Natural History in Pittsburgh for protection against possible bombing raids. The specimen, now dubbed CM 9380, is still mounted in Pittsburgh. After the war, the holotype of Dynamosaurus imperiosus and AMNH 5881 were also sold and now reside in the collections of the Natural History Museum, London (formerly the British Museum of Natural History), where they are known as BMNH R7994 and BMNH R7995, respectively. The American Museum of Natural History features AMNH 5027 in its famed Dinosaur Hall to this day.

Very few other Tyrannosaurus rex skeletons were discovered until the late 1980s. The skull of Nanotyrannus, frequently considered to be a juvenile T. rex, was recovered from Montana in 1942. In 1966, a crew working for the Natural History Museum of Los Angeles County under the direction of Harley Garbani discovered another T. rex (LACM 23844) which included most of the skull of a very large, mature animal. When it was put on display in Los Angeles, LACM 23844 was the largest T. rex skull on exhibit anywhere. Garbani also discovered several other partial skeletons over the next decade (including LACM 23845, holotype of "Albertosaurus" megagracilis), some of which are maintained in the collections of the University of California Museum of Paleontology in Berkeley, California. Other skulls and partial skeletons were discovered in South Dakota and Alberta, Canada in the early 1980s.^[4]

Before 1987, Tyrannosaurus rex was thought to be rare.^[4] However, the last two decades have seen the discovery and description of over a dozen additional specimens. The first, nicknamed "Stan" in honor of its discoverer, amateur paleontologist Stan Sacrison, was found in the Hell Creek Formation near Buffalo, South Dakota, in the spring of 1987. After 30,000 hours of digging and preparation by the Black Hills Institute, beginning in 1992, 65% of a skeleton emerged, including a complete skull. Stan (BHI 3033) is currently on display in the Black Hills Museum of Natural History in Hill City, South Dakota, after an extensive world tour, and replicas sold by the Black Hills Institute are also found in museum exhibit halls around the world. This specimen exhibits many bone pathologies, including broken and healed ribs, a broken and healed neck and a spectacular hole in the back of its head, about the size of a Tyrannosaurus tooth.^[5]

In 1988, local rancher Kathy Wankel discovered another Tyrannosaurus rex in Hell Creek sediments on an island in the Charles M. Russell National Wildlife Refuge of Montana. This specimen was excavated by a team from the Museum of the Rockies led by paleontologist Jack Horner, with assistance from the U.S. Army Corps of Engineers. The specimen, given the number MOR 555 but informally called the "Wankel rex," includes approximately 90% of the skeleton, including the skull, as well as what at the time was the first complete T. rex forelimb. It is now on exhibit at the Museum of the Rockies in Bozeman, Montana.^[4]

Susan Hendrickson of the Black Hills Institute discovered the best-preserved Tyrannosaurus currently known, in the Hell Creek Formation near Faith, South Dakota, on August 12, 1990. This specimen, named "Sue" in honor of its discoverer, soon became embroiled in a legal battle over its ownership. The land on which the fossil was discovered was found to lie within the Cheyenne River Indian Reservation and is occupied by the family of Maurice Williams, a Native American of the Sioux tribe. In 1992, Williams claimed he still owned the fossil, for which the Black Hills Institute had paid him USD 5,000. The local Cheyenne River Sioux Tribe, of which Williams is a member, also claimed ownership. The fossil, as well as many thousands of pages of field notes and business records, were confiscated by the Federal Bureau of Investigation in 1992 and held throughout the ensuing court proceedings. In 1997, the suit was settled in favor of Maurice Williams, due to the fact that his land is technically held in trust for him by the United States government. Therefore, although the Black Hills Institute had paid Williams for the fossil, it was judged that the fossil could be considered "land" which Williams owned but could not legally sell without government permission. The fossil was returned to Williams' ownership and Neal Larson, vice-president of the Black Hills Institute, was sentenced to two years in federal prison for an unrelated customs violation discovered by the FBI while searching through his business records. Williams quickly offered up "Sue" for auction by Sotheby's in New York, where it was sold to the Field Museum of Natural History in Chicago for USD 8.4 million — the highest price ever paid for a fossil. Preparation of "Sue" (FMNH PR2081) was completed at the Field Museum and her skeleton was placed on exhibit on May 17, 2000.^[6][7] Over 90% of the skeleton was recovered, allowing the first complete description of a Tyrannosaurus rex skeleton.^[8]

Following the sale of "Sue," another Tyrannosaurus rex skeleton, dubbed "Z-rex", was put up for auction on eBay in 2000 with an asking price of over USD 8 million. It failed to sell online but was purchased for an undisclosed price in 2001 by British millionaire Graham Ferguson Lacey, who renamed the skeleton "Samson" after the Biblical figure of the same name. This specimen, discovered on private land in South Dakota in 1992, includes a complete and undistorted skull, which was prepared by the Carnegie Museum in Pittsburgh starting in May 2004.^[9] After preparation was complete in March 2006, the specimen was returned to its owner, who plans to put it on an educational tour.^[10]

Jane

Scottie

B. rex and other MOR rexes (including soft tissue)

MOR 008

Tinker

[edit] Manospondylus controversy

The first fossil specimen which can be attributed to Tyrannosaurus rex (a partial vertebra) was found by Edward Cope in 1892 and was described as Manospondylus gigas.

In 2000, there was controversy regarding its name, because the dinosaur bones unearthed in South Dakota in June that year may have been part of a fossil known as Manospondylus gigas^[11][12]. According to the rules of International Commission on Zoological Nomenclature, the system that gives animals their Latin designation, Cope's 1892 name Manospondylus gigas should have priority, because his discovery came first. However, in the ICZN 4th edition, which took effect on January 1, 2000, Chapter 8, Article 35.5 stated that any such discovery made after 1999 does not cause the older name to replace the newer, prevailing name and that Tyrannosaurus is to be a nomen conservandum. Therefore, regardless of the result of the discovery, the Tyrannosaurus name is still used by biologists today ^[13].

In 2001, a 50% complete skeleton of a juvenile Tyrannosaurus was discovered in the Hell Creek Formation in Montana by a crew from the Burpee Museum of Natural History of Rockford, Illinois. Dubbed "Jane", the find was initially considered the first known skeleton of the pygmy tyrannosaurid Nanotyrannus but subsequent research has revealed that it is more likely a juvenile Tyrannosaurus. It is the most complete and best preserved juvenile example known to date. Jane has been examined by Jack Horner, Pete Larson, Robert Bakker, Greg Erikson and several other renowned paleontologists, because of the uniqueness of her age. Jane is currently on exhibit at the Burpee Museum of Natural History in Rockford, Illinois.

In the March 2005 Science magazine, Mary Higby Schweitzer of North Carolina State University and colleagues announced the recovery of soft tissue from the marrow cavity of a fossilized leg bone from a 68-million-year-old Tyrannosaurus. The bone had been intentionally, though reluctantly, broken for shipping, and then not preserved in the normal manner specifically because Schweitzer was hoping to test it for soft tissue. Designated as the Museum of the Rockies specimen 1125, or MOR 1125, the dinosaur was previously excavated from the Hell Creek Formation. Flexible, bifurcating blood vessels and fibrous but elastic bone matrix tissue were recognized. In addition, microstructures resembling blood cells were found inside the matrix and vessels. The structures bear resemblance to ostrich blood cells and vessels. However, since an unknown process distinct from normal fossilization seems to have preserved the material, the researchers are being careful not to claim that it is original material from the dinosaur ^[14]. The presence of medullary bones in this specimen is also of interest ^[15].

If it turns out to be original material, any surviving proteins may be used as a means of indirectly guessing some of the DNA content of the dinosaurs involved, because each protein is typically created by a specific gene. The absence of previous finds may merely be the result of people assuming preserved tissue was impossible, therefore simply not looking; since the first, two more tyrannosaurs and a hadrosaur have also been found to have such tissue-like structures. [1][2]

In a press release on April 7th 2006 Montana State University revealed that it possessed the largest Tyrannosaurs skull yet discovered. Discovered in the 1960s and only recently reconstructed, the skull measures 59 inches long compared to the 55.4 inches of “Sue’s” skull, a difference of 6.5%. [3] & [4]

[edit] The world of Tyrannosaurus

North America in the times of Tyrannosaurus had both familiar and strange elements. The soft-shelled turtles, crocodiles, pike (Esocidae), and gar (Lepisosteidae) alive at the time were quite similar to those living today. Frogs and monitor lizards were other familiar animals. Ferns, horsetails, palms, magnolias, southern beech, poplars, and shrubs were some of the dominant plants; grasses had evolved but were not yet widespread. Conifers such as sequoias, araucaria, pines, and cypresses were common. The North American T. rex probably lived in many different habitats, because of its broad range but many of the fossil sites in which it is commonly found appear to have been humid, subtropical forests. Birds with beaks were already around, including waterfowl. Other inhabitants of the landscape are more unfamiliar. There were birds with teeth and some of the giant pterosaurs still thrived, such as Quetzalcoatlus, which had an estimated wingspan of 12 m. Other theropods included dromaeosaurids, troodontids, and Ornithomimus, all of which appear to have been less than 4 or 5 meters long. Herds of Triceratops, Torosaurus and duck-billed dinosaurs (hadrosaurs) such as Edmontosaurus roamed the land. Other dinosaurian herbivores included armored Ankylosaurus, boneheaded Pachycephalosaurus and Stygimoloch and small ornithopods such as Bugenasaura and Thescelosaurus. Mammals (predominantly multituberculates and marsupials) were mostly small, shrew- to rat-sized nocturnal animals. Primitive primates may have been around (this issue is open to debate). Snakes had evolved by this time, very similar to some snakes today.

Tyrannosaurus is believed to have required extensive geographic feeding ranges, nearly as large as a U.S. state. Theropods the size of Tyrannosaurus arose in response to the retreat of the Western Interior Seaway of North America, 69 million years ago, which would have increased the size of the feeding range ^[16].

[edit] Paleobiology

As with all dinosaurs, much of the Tyrannosaurus biology, including lifespan, breeding strategy, coloration, ecology and physiology, remains unknown. A site in Alberta has at least nine individuals of Albertosaurus (a closely related animal) of different ages preserved together but whether these animals lived together or simply died together is unclear.

[edit] Size

A number of other giant carnivorous dinosaurs have been discovered, including Carcharodontosaurus, Giganotosaurus, Tyrannotitan, Mapusaurus, Torvosaurus, Acrocanthosaurus and a giant species of Allosaurus. Giganotosaurus appears to have been larger than Tyrannosaurus - longer, although possibly not as heavy. In the film Jurassic Park 3, Spinosaurus is depicted as being larger than Tyrannosaurus and fossils described in 2006 support this, showing that Spinosaurus was about 4 meters longer and 4 tons heavier than Tyrannosaurus (a size comparison of the largest theropods can be found in the article Dinosaur size). There is still no clear scientific explanation for exactly why these animals grew so much larger than the predators that came before and after them.

[edit] Growth Rate

[edit] Posture

For over 50 years, Tyrannosaurus had been depicted as a 'living tripod', with the body at 45 degrees or less from vertical and the tail dragging along the ground and acting as a balance for the legs. This dated from around 1906, when Osborn, who believed it stood upright, was preparing a Tyrannosaurus skeleton for display at the American Museum of Natural History in New York. It stood this way for over half a century until it was dismantled in 1992. The depictions in many paintings, such as the mural Age Of Reptiles by Rudolph Zallinger in the Peabody Museum Of Natural History at Yale University, and films continued in this manner until the 1990s, when such films such as Jurassic Park showed Tyrannosaurus with its body parallel to the ground.

[edit] Feathers

Main article: Feathered dinosaurs

It has been proposed that Tyrannosaurus and other theropod dinosaurs may have had feathers. Small coelurosaurs (a closely-related dinosaur group) from the Yixian Formation in Liaoning, China, have been discovered with either pennaceous feathers or fur-like 'protofeathers', which suggest the possibility that tyrannosaurids may also have borne feathers. In 2004, the primitive tyrannosauroid Dilong was discovered, from the same formation and showed evidence of long tail plumes. However, skin impressions from adult tyrannosaurs in Alberta and Mongolia appear to show the pebbly scales typical of other dinosaurs. This would be consistent with the creature's size, as at 8 tons the warm-blooded tyrannosaur's heat dispersal would actually have been impeded by a covering of feathers. It is possible that Tyrannosaurus evolved to lose any feathers its ancestors may have had, as with the hair of modern elephants and hippos.

[edit] Arms

When Tyrannosaurus was first discovered, the forelimbs were still unknown. For the initial mounted skeleton, as seen by the public, Osborn substituted three-fingered Allosaurus forelimbs. However, in 1914, Lambe demonstrated the closely-related Albertosaurus had two-fingered forelimbs. Complete forelimbs were only found recently, in 1989. The 'arms' are relatively tiny, at 1 metre (3 feet) long, yet very muscular. Their purpose is unknown. The muscle placement indicates a restricted range of movement but great strength. Judging from their size, relative to the animal as a whole, it is very unlikely that they took any part in locomotion or in saving the animal's balance, were it to have fallen.

They may have been used for grasping during mating, as aids in rising from a lying position or perhaps to pin meat against the body while dragging a carcass, to prevent it swinging around.

[edit] Bite Force

[edit] Intelligence and senses

[edit] Speed

Scientists who think that Tyrannosaurus was able to run slowly point out that hollow Tyrannosaur bones and other features that would have lightened its body may have kept adult weight to a mere 5 tonnes or so,^[17] or that other animals like ostriches and horses with long, flexible legs are able to achieve high speeds through slower but longer strides. Additionally, some have argued that Tyrannosaurus had relatively larger leg muscles than any animal alive today, which could have enabled fast running (40-70 km/h or 25-45 mph).

Some old studies of leg anatomy and living animals suggested that Tyrannosaurus could not run at all and merely walked. The ratio of femur (thigh bone) to tibia (shank bone) length (greater than 1, as in most large theropods) could indicate that Tyrannosaurus was a specialized walker, like modern elephants. In addition, it had tiny 'arms' that could not stop the dinosaur's fall if it stumbled while running; standard estimates of Tyrannosaurus weight at 6 to 8 tonnes would produce a lethal impact force if the dinosaur fell. It should be noted, however, that giraffes have been known to gallop at 50 km/h (31 mph);^[18] at those speeds, the animal risks breaking a leg or worse, which can be fatal even when the accident occurs in "safe" environments such as zoos.^[19] If it could run, Tyrannosaurus may have been a risk-taker, in much the same way as animals alive today are. Yet estimates of leg bone strength in Tyrannosaurus show that its legs were little if any stronger than those of elephants, which are relatively limited in their top speed and don't ever become 'airborne'.

Walking proponents estimate the top speed of Tyrannosaurus at about 17 km/h (11 mph). This is still faster than the most likely prey species that co-existed with tyrannosaurs: hadrosaurs and ceratopsians ^[20]. In addition, some predation advocates claim that tyrannosaur running speed is not important, since it may have been slow but better designed for speed than its probable prey ^[21] or it may have used ambush tactics to attack faster prey animals.

The most recent research on Tyrannosaurus locomotion does not specify how fast it may have run but admits that there is little capacity to narrow down speeds further than a range from 17 km/h (11 mph), which would be only walking or slow running, to 40 km/h (25 mph), which would be moderate-speed running. For example, a paper in Nature (Hutchinson & Garcia 2002) used a mathematical model (validated by applying it to a wide range of living animals) to gauge the leg muscle mass needed for fast running (over 25 mph). They found that proposed top speeds in excess of 40 km/h (25 mph) were unfeasible, because they would require very large leg muscles (more than approximately 40-86% of total body mass ^[22]). Even moderately fast speeds would have required large leg muscles. This discussion is difficult to resolve, as it is unknown how large the leg muscles were. If they were smaller, only ~11 mph walking/jogging might have been possible.

[edit] Feeding strategy

Most debate about Tyrannosaurus centers on its feeding patterns and locomotion. One paleontologist, noted hadrosaur expert Jack Horner, claims that Tyrannosaurus was exclusively a scavenger and did not engage in active hunting at all ^[23]. Horner has only presented this in an official scientific context once, mainly discussing it in his books and in the media. His hypothesis is based on the following: Tyrannosaurs have large olfactory bulbs and olfactory nerves (relative to their brain size). These suggest a highly developed sense of smell, allegedly used to sniff out carcasses over great distances. Tyrannosaur teeth could crush bone, a skill perhaps used to extract as much food (bone marrow) as possible from carcass remnants, usually the least nutritious parts. Since at least some of Tyrannosaurus's prey could move quickly, evidence that it walked instead of ran could indicate that it was a scavenger (see more on this below) ^[24].

Most scientists who have published on the subject since insist that Tyrannosaurus was both a predator and a scavenger, taking whatever meat it could acquire, depending on the opportunity that was presented ^[25]. Modern carnivores are seldom strict predators or scavengers. Lions, for example, sometimes scavenge prey that hyenas have killed (and vice versa). Scavenging behavior depends upon prey availability, among other factors.

Some evidence exists that suggests hunting behavior in Tyrannosaurus. The ocular cavities of Tyrannosaurs are positioned so that the eyes would point forward, giving the dinosaur binocular vision. A scavenger might not need the advanced depth perception that stereoscopic vision affords; in modern animals, binocular vision is found primarily in predators. Bite marks in other animals and even other tyrannosaur fossils suggest predatory behavior.

When examining Sue, paleontologist Peter Larson found a broken and healed fibula (calf bone) and tail vertebrae, scarred facial bones and a tooth from another Tyrannosaurus embedded in a neck vertebra. If correct, it might be strong evidence for aggressive behavior between tyrannosaurs but whether it would be competition for food and mates or active cannibalism is unclear. However, more recent investigation of these purported wounds has shown that most are infections rather than injuries (or simply damage to the fossil after death) and the few injuries are too general to be indicative of intraspecific conflict. In the Sue excavation site, an Edmontosaurus annectens skeleton was also found with healed tyrannosaur-inflicted scars on its tail. The fact that the scars seem healed suggests active predation instead of scavenging a previous kill. Another piece of evidence is a Triceratops found with a third of its horn missing and a tooth mark along a piece of frill. Again, these were inflicted by a tyrannosaur and they too appear healed.

For all intents and purposes, the "scavenging debate" does not actually exist in any scientific context. However, there have been conflicting studies regarding the extent to which Tyrannosaurus could run and exactly how fast it might have been; speculation has been up to 70 km/h (45 mph) or even more.

Some argue that if Tyrannosaurus were a scavenger, another dinosaur had to be the top predator in the Amerasian Upper Cretaceous. Top prey were the larger marginocephalians and ornithopods. The other tyrannosaurids share so many characteristics that only small dromaeosaurs remain a choice as top predators. In this light, scavenger hypothesis adherents have hypothesized that the size and power of tyrannosaurs allowed them to steal kills from smaller predators.

[edit] Appearances in popular culture

Main article: Tyrannosaurus in popular culture

Since it was first described in 1905, Tyrannosaurus has become the most widely-recognised dinosaur in popular culture. It is the only dinosaur which is commonly referred to by its specific name, Tyrannosaurus rex, among the general public, and the scientific abbreviation T. rex (often mistakenly spelled "T-Rex") has also come into wide usage.^[8] Museum exhibits featuring T. rex are very popular; an estimated 10,000 visitors flocked to Chicago's Field Museum on the opening day of its "Sue" exhibit in 2003.^[26] T. rex has appeared numerous times on television and in movies, notably King Kong and Jurassic Park. A number of books and comic strips, including Calvin and Hobbes, have also featured Tyrannosaurus, which is typically portrayed as the biggest and most terrifying carnivore of all. Tyrannosaurus-related toys, video games, and other merchandise remain popular. Various businesses, notably Sinclair Oil, have capitalized on the popularity of Tyrannosaurus rex by using it in advertisements.

[edit] References

1. ^ ^{a b} Osborn, H.F. 1905. Tyrannosaurus and other Cretaceous carnivorous dinosaurs. Bulletin of the American Museum of Natural History 21: 259-265. (download here)
2. ^ Osborn, H.F. 1906. Tyrannosaurus, Upper Cretaceous carnivorous dinosaur (second communication). 22: 281-296. (download here)
3. ^ Osborn, H.F. 1913. Tyrannosaurus: restoration and model of the skeleton. Bulletin of the American Museum of Natural History 32: 91-92. (download here)
4. ^ ^{a b c} Horner, J.R. & Lessem, D. 1993. The Complete T. rex New York: Simon & Schuster. 238pp.
5. ^ "STAN T. rex" Black Hills Institute for Geological Research, Inc. 2004. Retrieved July 16, 2005.
6. ^ "The Story of a Dinosaur Named Sue" by Neal Larson. Black Hills Institute of Geological Research, Inc. May 19, 2000. Retrieved July 16, 2006.
7. ^ "Sue at the Field Museum" Field Museum of Natural History. September 9, 2005. Retrieved July 16, 2006.
8. ^ ^{a b}
9. ^ "Carnegie Museum digs into controversial, but promising T-rex skull" by Byron Spice. Pittsburgh Post-Gazette. May 12, 2004. Retrieved July 16, 2006.
10. ^ "It's "Bone Voyage" for a famous fossil" by Dan Lagiovane. Carnegie Museum of Natural History. March 2, 2006. Retrieved July 16, 2006.
11. ^ Discovery could Endanger T. rex Name. Retrieved on December 11, 2005.
12. ^ :: Discovery Channel CA ::. Retrieved on December 11, 2005.
13. ^ So why hasn't Tyrannosaurus been renamed Manospondylus?. Retrieved on December 11, 2005.
14. ^ BBC NEWS : Science/Nature : T. rex fossil has 'soft tissues'. Retrieved on December 11, 2005.
15. ^ http://www.washingtonpost.com/wp-dyn/content/article/2005/06/03/AR2005060300141.html. Retrieved on December 11, 2005.
16. ^ Scientific American, 290, no. 2, February 2004 pp. 23-24.
17. ^
18. ^ Giraffe. WildlifeSafari.info. Retrieved on 2006-04-29.
19. ^ The History of Woodland Park Zoo - Chapter 4. Retrieved on 2006-04-29.
20. ^ Hutchinson, J. R. and Garcia, M. (2002). Tyrannosaurus was not a fast runner. Nature 415: 1018-1021
21. ^ Unearthing T. rex : T.rex In-Depth : Traits (See above). Retrieved on December 11, 2005.
22. ^ http://www.priweb.org/ed/ICTHOL/ICTHOL04papers/86.htm. Retrieved on December 11, 2005.
23. ^ Horner, J.R. and Lessem, D. (1993). The Complete T. rex: How Stunning New Discoveries Are Changing Our Understanding of the World's Most Famous Dinosaur. New York: Simon & Schuster.
24. ^ Horner, J.R., (1994). Steak knives, beady eyes, and tiny little arms (a portrait of Tyrannosaurus as a scavenger). The Paleontological Society Special Publication 7: 157-164.
25. ^ Farlow, J. O. and T. R. Holtz, Jr. 2002. The fossil record of predation in dinosaurs. pp. 251–266, in M. Kowalewski and P. H. Kelley (eds.), The Fossil Record of Predation. The Paleontological Society Papers 8.
26. ^ Guinness World Records Ltd. 2003. 2003 Guinness World Records. p. 90.

• Carpenter, K. (1998). "Evidence of predatory behavior by carnivorous dinosaurs.". Gaia 15: 135-144.
• Farlow, J. O.; Smith, M. B.; Robinson, J. M. (1995). "Body mass, bone "strength indicator", and cursorial potential of Tyrannosaurus rex". Journal of Vertebrate Paleontology 15 (4): 713–725.
• Holtz, T. R. (1994). "The phylogenetic position of the Tyrannosauridae: implications for theropod systematics". Journal of Paleontology 68 (5): 1100–1117.
• Horner, John R.; Lessem, Don (1993). The Complete T. Rex./How Stunning New Discoveries Are Changing Our Understanding of the World's Most Famous Dinosaur. Simon and Schuster. ISBN 0-671-74185-3.
• Hutchinson, John R.; Garcia, Mariano (2002). "Tyrannosaurus was not a fast runner". Nature 415: 1018–1021. DOI:10.1038/4151018a.
• Meers, Mason B. (August 2003). "Maximum Bite Force and Prey Size of Tyrannosaurus rex and Their Relationships to the Inference of Feeding Behavior". Historical Biology: A Journal of Paleobiology 16 (1): 1 - 12. DOI:10.1080/0891296021000050755.
• Osborn, Henry Fairfield (1905). "Tyrannosaurus and other Cretaceous carnivorous dinosaurs". Bulletin of the American Museum of Natural History 35: 733–771.
• Osborn, Henry Fairfield (1917). "Skeletal adaptations of Ornitholestes, Struthiomimus, Tyrannosaurus". Bulletin of the American Museum of Natural History 35: 733–71.
• Schweitzer, Mary H.; Wittmeyer, Jennifer L.; Horner, John R.; Toporski, Jan K. (25 March 2005). "Soft-Tissue Vessels and Cellular Preservation in Tyrannosaurus rex". Science 307 (5717): 1952–1955. DOI:10.1126/science.1108397.

[edit] External Links

• "The secret of T. rex's colossal size: a teenage growth spurt", The Guardian, August 12, 2004.
• Sue's homepage
• Stan's homepage
• Pictures of a replica of Sue the T. rex
• History of the first T. rex finds
• Tree of Life discussing Tyrannosauridae
• Unearthing Tyrannosaurus rex
• T.rex juvenile Jane
• Cretaceous Hell Creek Faunal Facies is an example of one tyrannosaur environment, in the Hell Creek Formation of Montana
• Image of T. rex.
• Bristol University study on bite forces of predators
• Museum of Unnatural Mystery - Bite force etc. of T. rex
• University of Tampa on bite force etc. of T. rex
• Stanford University on bite force of T. rex
• [http://www.weirdnwildcreatures.com/dbcreatures/maker.php?creature=11