Tyrannosaurus is a genus of theropod coelurosaurian dinosaurs. The species Tyrannosaurus rex ( rex meaning "king" in Latin) is often colloquially called just T- Rex is one of the most represented of the great theropods. Tyrannosaurus lives throughout the area now in western North America, in what was then the continent of the island known as Laramidia. Tyrannosaurus has a much wider range than other tyrannosaurids. Fossils are found in various rock formations dating from the Late Cretaceous Maastrichtian period, 68 to 66 million years ago. It was the last known tyrannosaurids member, and among the last non-avian dinosaurs that existed before the Cretaceous-Paleogene extinction event.
Like other tyrannosaurids,
More than 50 specimens from Tyrannosaurus rex have been identified, some of which are almost complete skeletons. Soft tissue and protein have been reported at least in one of these specimens. The abundance of fossil materials has enabled significant research into many aspects of biology, including its life history and biomechanics. The eating habits, physiology and potential velocities of Tyrannosaurus rex are some of the subjects of debate. The taxonomy is also controversial, as some scientists consider Tarbosaurus bataar from Asia to be the second species of Tyrannosaurus while the other maintains Tarbosaurus is a separate genus. Several other North American tyrannosaurids genera have also been amamonized by Tyrannosaurus .
As the theropod archetypal, Tyrannosaurus (commonly referred to as T. Rex ) is one of the most famous dinosaurs since the 20th century, and has been featured in movies, ads, and postage stamps, as well as many other types of media.
Video Tyrannosaurus
Deskripsi Edit
Tyrannosaurus rex is one of the largest land carnivores of all time; The largest complete specimen, located at the Field Museum of Natural History with the names FMNH PR2081 and nicknamed Sue, measured 12.3 meters (40Ã, ft) in length, and 3.66 meters (12Ã, ft) high in the hip, and according to most recent studies estimated to weigh between 8.4 metric tons (9.3 tons short) to 14 metric tons (15.4 short tons) when alive. Not all of the adult specimens found in Tyrannosaurus were large. Historically the average adult mass estimate has varied widely over the years, from as low as 4.5 metric tons (5.0 tonnes short), to more than 7.2 metric tons (7.9 tonnes short), with estimates most modern ranged between 5.4 metric tons (6.0 tons short) and 8.0 metric tons (8.8 tons short). Hutchinson et al. (2011) found that the maximum weight of Sue, complete specimens complete Tyrannosaurus , is between 9.5 and 18.5 metric tons (9.3 to 18.2 tons in length; 10.5 to 20.4 shorts), although the authors state that their top and bottom estimates are based on models with wide bar errors and that they "assume [they are] too thin, too fat, or too disproportionate" and provide an average estimate of 14 metric tons (15.4 short tons) for this specimen. Packard et al. (2009) tested the method of estimating the mass of dinosaurs on elephants and concluded that dinosaurs were defective and resulted in excessive estimates; thus, the weight of Tyrannosaurus , as well as other dinosaurs, could be much less. Other estimates have concluded that the largest known specimen of Tyrannosaurus has a mass close to or exceeding 9 tons.
Due to the relatively small amount of recovered specimens and large populations of individuals present at certain times when Tyrannosaurus is still alive, there may be larger specimens than currently known including "Sue", despite the discovery of these greatest individuals may forever be untenable because of the incomplete nature of the fossil record. Holtz also stated that "it is reasonable to suppose that there are individuals who are 10, 15, or even 20 percent larger than Sue in any T. rex population."
The neck
The largest skull Tyrannosaurus rex is 1.52 meters (5 feet) in size. Large fenestrae (openings) in the skull reduce weight and provide an area for muscle attachment, as in all carnivorous theropods. But in another case the skull Tyrannosaurus is significantly different from that of a large non-tyrannosauroid theropod. It's very wide on the back but has a narrow snout, allowing incredible binocular vision. The bones of the skull are very large and the nose and some other bones are fused, preventing movement between them; but many have pneumatization (containing "honeycomb" from a small air space) that may have made the bones more flexible and lighter. These and other skull-boosting features are part of the tyrannosaurid trend toward an increasingly powerful bite, which easily surpasses all non-tyrannosaurids. The U-shaped upper jaw tip (most non-tyrannosauroid carnivores have a V-shaped upper jaw), which increases the amount of tissue and the tyrannosaur bone can rip with one bite, although it also increases the pressure on the front. tooth.
The teeth Tyrannosaurus rex are shown marked heterodontic (form difference). The premaxillary teeth in front of the upper jaw are tight, D - a cross-section shape, having bulges on the back surface, which are insisiform (edges like carving knives) and curved. to the back. The D -section section, strengthening the back and the backward curve reduces the risk that the tooth will break when Tyrannosaurus bites and pulls. The remaining teeth are strong, like "deadly bananas" rather than daggers, wider and also have a stronger bulge. Those in the upper jaw are bigger than all except the back of the lower jaw. The largest discovered so far is estimated to be 30.5 centimeters (12 inches) including the roots when the animal is alive, making it the largest tooth of the found carnivorous dinosaurs.
Skin and feathers that may Edit
Although there is no direct evidence for furry Tyrannosaurus rex, many scientists now consider the possibility that T.Ã, rex has a fur on at least parts of its body, because of their presence at related species. Mark Norell of the American Museum of Natural History sums up the balance of evidence by stating that: "We have plenty of evidence that Hairy T. rex, at least for several stages of his life, as we do it Australopithecines like Lucy have hair. "
The first evidence for feathers in tyrannosauroids originated from the small species Dilong paradoxus, found in the Chinese Yixian Formation, and reported in 2004. Like many other coelurosaurian theropods found in Yixian, the fossil skeleton is preserved with a layer of stringy structures which are generally acknowledged as precursors of feathers. Since all known skin impressions of the larger tyrannosauroids known at the time show proof of scale, researchers studying Dilong speculated that feathers may be negatively correlated with body size - that teens may have hairy, then let go feathers and scales are only declared as animals become larger and no longer required isolation to keep warm. Subsequent findings show that even some large tyrannosauroids have feathers covering most of their bodies, raising doubts on the hypothesis that they are feature-related sizes.
While the skin traces of the Tyrannosaurus rex specimen dubbed "Wyrex" (BHI 6230) found in Montana in 2002, as well as several other giant tyrannosauroid specimens, show at least a small patch of mosaic scale, others, such as <<> Yutyrannus huali (whose length is up to 9 meters (30 feet) and weighs about 1,400 kilograms (3,100 pounds)), maintains feathers in various parts of the body, strongly suggesting that the whole body is covered in feathers. It is possible that the extent and nature of the fur covering the tyrannosauroid may have changed over time in response to body size, warmer climates, or other factors. By 2017, based on a skin impression found on the tail, ilium and neck of the specimen "Wyrex" (BHI 6230) and other related tyrannosaurids, it is suggested that large scaly tyrannosaurids and, if partially hairy, are limited. to dorsum.
A study in 2016 proposed that large theropods such as Tyrannosaurus had closed-lip teeth like lizards that remained and instead of naked teeth like crocodiles. This is based on the existence of enamel, which according to the research needs to remain hydrated, a problem not encountered by aquatic animals such as crocodiles or toothless animals such as birds.
Based on a comparison of bone texture Daspletosaurus with an existing crocodile, a detailed study in 2017 by Thomas D. Carr et al. found that tyrannosaurs had large, flat scales on their muzzles.. At the center of the scales there is a small keratinization patch. In crocodiles, such patches cover a collection of sensory neurons that can detect mechanical, thermal and chemical stimuli. They proposed that tyrannosaurs might also have sensory neuron bundles under their facial scales and may have used them to identify objects, measure their nest temperatures and gently take eggs and hatchlings. Although the study did not explicitly discuss evidence for or against the lips, many major news outlets regarded it as evidence against tyrannosaurs having lips. The comparison with crocodile facial tissue and Thomas D. Carr's personal interpretation of the findings was cited as support for the conclusion that tyrannosaurs lacked lips.
Maps Tyrannosaurus
History of research Edit
Henry Fairfield Osborn, president of the American Museum of Natural History, was named Tyrannosaurus rex in 1905. The generic name is derived from the Greek word ???????? ( tyrannos , meaning "tyrant") and ?????? ( sauros , meaning "lizard"). Osborn uses the Latin rex , which means "king", for a particular name. Therefore, full binomial translates into "tyrant lizard the king" or "King Tyrant Lizard", emphasizing the size of the animal and the perceived dominance of other species at the time.
Oldest Findings Edit
The tooth of what is now documented as Tyrannosaurus rex was discovered in 1874 by Arthur Lakes near Golden, Colorado. In the early 1890s, John Bell Hatcher collected postcranial elements in eastern Wyoming. Fossils are believed to belong to a large species of Ornithomimus ( O. grandis ) but are now considered Tyrannosaurus rex fixed. The vertebral fragments discovered by Edward Drinker Cope in western South Dakota in 1892 and assigned to Manospondylus gigas have also been recognized as belonging to
Barnum Brown, assistant curator of the American Museum of Natural History, discovered the first partial skeleton of Tyrannosaurus rex in eastern Wyoming in 1900. HF Osborn originally named this skeleton Dynamosaurus imperiosus on paper in 1905 Brown found another partial skeleton in the Hell Creek Formation in Montana in 1902. Osborn used this holotype to describe Tyrannosaurus rex in the same paper where D. imperiosus was described. In 1906, Osborn acknowledged both as a synonym, and acted as the first proof by choosing Tyrannosaurus as a valid name. The original material Dynamosaurus is in the Natural History Museum collection, London.
In total, Brown found five partial skulls' Tyrannosaurus . In 1941, Brown's invention of 1902 was sold to the Carnegie Museum of Natural History in Pittsburgh, Pennsylvania. The fourth and largest invention of Brown, also from Hell Creek, is on display at the American Museum of Natural History in New York.
Manospondylus Edit
The first named fossil specimen that can be associated with Tyrannosaurus rex consists of two partial vertebrae (one of which has been lost) was discovered by Edward Drinker Cope in 1892. Cope believes that they belong to dinosaurs "agathaumid" (Ceratopsid) and named them Manospondylus gigas , meaning "giant porous vertebrae" which refers to many holes for blood vessels that he found in the bones. The M. gigas remain later identified as those who are theropod rather than ceratopsid, and H.F. Osborn acknowledged the similarity between M. gigas and Tyrannosaurus rex as early as 1917. Due to the fragmentary nature of the Manospondylus vertebra , Osborn did not synonymize the two genera.
In June 2000, the Black Hills Institute placed the type of locality M. gigas in South Dakota and found more tyrannosaur bones there. This is judged to represent the further remnants of the same individual, and becomes synonymous with those of Tyrannosaurus rex . According to the International Code of Zoological Nomenclature (ICZN) rules, the system governing the scientific naming of animals, Manospondylus gigas should have priority over Tyrannosaurus rex , therefore named first. The fourth edition of ICZN, which came into force on 1 January 2000, states that "applicable usage must be preserved" when "senior synonyms or homonyms have not been used as valid names after 1899" and "junior or homonymous synonyms have been used for certain taxon, as it is considered a legitimate name, in at least 25 works, published by at least 10 authors in the previous 50 years... " Tyrannosaurus rex may qualify as a valid name under these circumstances and will most likely be considered nomen protectum ("name protected") under ICZN if it has ever been published officially, which has not. Manospondylus gigas can then be considered as nomen oblitum ("forgotten name").
Famous specimens Edit
Sue Hendrickson, an amateur paleontologist, found the most complete fossil skeleton (about 85%) and the largest known fossil skeleton known as the Hell Creek Formation near Faith, South Dakota, on August 12, 1990. This is Tyrannosaurus , dubbed Sue in his honor, is the object of a legal battle over his possession. In 1997 it was completed to support Maurice Williams, the original landowner. The fossil collection was purchased by the Field Museum of Natural History at a $ 7.6 million auction, making it the most expensive dinosaur skeleton to date. From 1998 to 1999, the Field Museum of Natural History preparation spent more than 25,000 man-hours to retrieve stones from each bone. The bone was then sent to New Jersey where the mountain was made. The mounts are completed then separated, and along with the bone, are sent back to Chicago for final assembly. The skeleton was open to the public on May 17, 2000 in the large hall (Stanley Field Hall) at the Field Museum of Natural History. A study of the fossil bones of this specimen shows that Sue reaches full size at age 19 and dies at age 28, the longest known tyrannosaur has lived. Initial speculation that Sue may have died from biting the back of the head has not been confirmed. Although subsequent research showed a lot of pathology in the bones, no bite marks were found. Damage to the back of the skull may be caused by post-mortem trampling. Recent speculation indicates that Sue may have died of starvation after contracting a parasitic infection from eating sick meat; The infections will cause inflammation in the throat, eventually causing Sue to starve because she can no longer swallow food. This hypothesis is evidenced by fine-eyed holes in the skull that are similar to those caused in modern birds with the same parasite.
Another Tyrannosaurus, dubbed Stan, in honor of the amateur paleontologist Stan Sacrison, was discovered in the Hell Creek Formation near Buffalo, South Dakota, in the spring of 1987. It was not collected until 1992, as it was mistakenly regarded as a skeleton Triceratop . Stan was 63% complete and exhibited at the Black Hills Institute of Geological Research in Hill City, South Dakota, after extensive world tours during 1995 and 1996. This tyrannosaur, too, was found to have many bone pathologies, including broken and healed ribs, broken neck (and healed) and a spectacular hole in the back of his head, the size of a Tyrannosaurus tooth.
In the summer of 2000, Jack Horner discovered five skeletons of Tyrannosaurus near the Fort Peck Reservoir in Montana. One of the specimens reported is probably the largest Tyrannosaurus ever found.
In 2001, a complete 50% skeleton of the Tyrannosaurus teenagers was found at Hell Creek Formation in Montana, by a crew from the Burpee Museum of Natural History in Rockford, Illinois. Nicknamed Jane, the discovery was originally considered the first known skeleton of the tyrannosaurid pygmy nanotyrannus but subsequent research has revealed that it is more likely to be a Tyrannosaurus teenager. This is the most complete and lasting example of teenagers known to date. Jane has been examined by Jack Horner, Pete Larson, Robert Bakker, Greg Erickson, and several other notable paleontologists, due to the uniqueness of his age. Jane is currently on display at the Burpee Museum of Natural History in Rockford, Illinois.
In a press release in 2006, Montana State University revealed that it has the largest Tyrannosaurus skull ever found. Discovered in 1960 and recently reconstructed, the skull measures 59 inches (150 cm) in length compared to the 55.4-inch (141 cm) Sue skull, 6.5% difference.
Classification Edit
Tyrannosaurus is a genus type of superfamily Tyrannosauroidea, Tyrannosauridae family, and Tyrannosaurinae subfamily; in other words it is the standard by which paleontologists decide whether to include other species in the same group. Other members of the tyrannosaurine subfamily include North America Daspletosaurus and Asia Tarbosaurus , both of which have sometimes been synchronized with Tyrannosaurus . Tyrannosaurids were formerly generally thought to be descendants of earlier large theropods such as megalosaurs and carnosaurs, although they have recently been reclassified with generally smaller coelurosaurs.
In 1955, Soviet paleontologist Evgeny Maleev named the new species, Tyrannosaurus bataar , from Mongolia. By 1965, this species had been renamed Tarbosaurus bataar . Although renamed, many phylogenetic analyzes have found Tarbosaurus bataar as a Tyrannosaurus rex , and is often regarded as an Asian species of Tyrannosaurus . I. A recent redescription of the skull Tarbosaurus bataar has shown that it is much narrower than that of Tyrannosaurus rex and that during the bite, the pressure distribution in the skull will have been very different, closer with those from Alioramus , other Asian tyrannosaurs. A related related analysis found that Alioramus , not Tyrannosaurus , was a taxon sister of Tarbosaurus , which, if true, would indicate that Tarbosaurus and Tyrannosaurus should remain separate. The discovery and description of Qianzhousaurus will then disprove this and reveal that Aladeamus belongs to Aladeamini clade. The discovery of tyrannosaurid Lythronax further demonstrates that Tarbosaurus and Tyrannosaurus are closely related, forming a clade with fellow Asian tyrannosaurids Zhuchengtyrannus , with Lythronax being their sister's taxi. A further study from 2016 by Steve Brusatte, Thomas Carr et al., Also shows that Tyrannosaurus may be an immigrant from Asia, as well as a possible offspring of Tarbosaurus. This study further suggests the possibility that Tyrannosaurus may have induced other native tyrannosaurids into North America to become extinct through the competition. Another finding in 2006 showed that giant tyrannosaurs may have existed in North America since 75 million years ago. Whether or not this specimen belongs to Tyrannosaurus rex , new species Tyrannosaurus , or a whole new genus is still unknown.
Other tyrannosaurid fossils found in the same formations as Tyrannosaurus rex were originally classified as separate taxa, including Aublysodon and Albertosaurus megagracilis , the latter < i> Dinotyrannus megagracilis in 1995. This fossil is now universally considered to belong to the teenagers
Below is a Tyrannosauridae cladogram based on the phylogenetic analysis performed by Loewen
Paleobiology Edit
Live history Edit
Identification of some specimens as adolescent Tyrannosaurus rex has enabled scientists to document ontogenetic changes in species, estimate lifespan, and determine how quickly animals will grow. The smallest known individual (LACM 28471, "Jordan theropod") is estimated to weigh only 30 kg (66 pounds), while the largest, such as FMNH PR2081 (Sue) is likely to weigh about 5,650 kg (12,460 pounds). The histologic analysis of bone Tyrannosaurus rex showed LACM 28471 was only 2 years old when it died, while Sue was 28 years old, an age likely to be near maximum for species.
Histology also allows the age of other specimens to be determined. Growth curve can be developed when the age of different specimens is plotted on the graph along with its mass. A Tyrannosaurus rex S-shaped growth curve, with teenagers remaining under 1,800 kg (4,000 pounds) to about 14 years, when body size begins to increase dramatically. During this rapid growth phase, a young Tyrannosaurus rex will get an average of 600 kg (1,300 pounds) per year over the next four years. At 18 years of age, the highlands curve again, indicating that growth slowed dramatically. For example, only 600 kg (1,300 pounds) separates the 28-year-old Sue from a 22-year-old Canadian specimen (RTMP 81.12.1). Histological studies of 2004 conducted by different workers corroborated these results, finding that rapid growth began to slow down in about 16 years.
Other studies corroborate the results of recent studies but found growth rates to be much faster, finding it to be around 1800 kilograms (4000 pounds). Although these results are much higher than previous estimates, the authors note that these results significantly decrease the large differences between actual and expected growth rates of animals of their size. Sudden changes in growth rates at the end of growth acceleration may indicate physical maturity, a hypothesis supported by the discovery of medullary tissue in the femur of 16 to 20 years of Tyrannosaurus rex from Montana (MOR 1125, also known as B -rex). Medullary tissue is found only in female birds during ovulation, indicating that B-rex is the reproductive age. Further studies show age 18 for this specimen. By 2016, it was finally confirmed by Mary Higby Schweitzer and Lindsay Zanno et al that the soft tissue in the MOR 1125 fungus is a medullary tissue. It also confirms the identity of the specimen as a female. The discovery of medullary bone tissue in Tyrannosaurus may prove valuable in determining the sex of other dinosaur species in future examinations, as the chemical makeup of the medullary tissue is clear. Other Tyrannosaurids exhibit very similar growth curves, albeit with lower growth rates corresponding to their lower adult size.
More than half of the specimens known as Tyrannosaurus rex appear to have died within six years of reaching sexual maturity, a pattern that is also seen in other tyrannosaurs and in some of today's large birds and mammals. This species is characterized by high infant mortality rates, followed by relatively low mortality among adolescents. Death increases again after sexual maturity, partly because of reproductive stress. One study showed that the scarcity of adolescent fossils As the number of known specimens increases, scientists begin analyzing variations between individuals and discover what appears to be two distinct body types, or morphs , similar to some other theropod species. As one of these more solidly built morphs, it's called a 'strong' morph while the other is called 'gracile'. Several morphological differences associated with the two morphs are used to analyze sexual dimorphism in Tyrannosaurus rex, with a 'strong' morph usually advised to be female. For example, the pelvis of some 'strong' specimens seems to be wider, perhaps to allow the passage of the egg. It is also assumed that 'strong' morphology is correlated with reduced chevron in the first tail vertebra, as well as allowing the egg to escape from the reproductive tract, as has been reported erroneously for crocodiles. In recent years, evidence of sexual dimorphism has weakened. A 2005 study reported that previous claims of sexual dimorphism on the erroneous crocodile chevron anatomy, raises doubts in the presence of similar dimorphisms between the sex tyrannosaurus rex . A full-sized chevron was found on Sue's first tail vertebra, a very powerful individual, suggesting that this feature can not be used to distinguish two morphs. Like the Tyrannosaurus rex specimens have been found from Saskatchewan to New Mexico, differences between individuals may be indicative of geographical variations rather than sexual dimorphism. Differences can also be related to age, with individuals 'strapping' into older animals. Only one specimen Tyrannosaurus rex is conclusively proven to belong to a particular gender. The B-rex examination shows the preservation of soft tissue in some bones. Some of these tissues have been identified as medullary tissue, a special tissue that grows only in modern birds as a source of calcium for eggshell production during ovulation. Because only female birds lay eggs, medullary tissue is found only naturally in women, although men are able to produce when injected with female reproductive hormones such as estrogen. This strongly suggests that B-rex is female, and that she died during ovulation. Recent research has shown that medullary tissue is never found in crocodiles, which are considered to be nearest dinosaur relatives, other than birds. The joint presence of medullary tissue in birds and theropod dinosaurs is further evidence of the close evolutionary relationship between the two. Posture Edit
Modern representations in museums, art, and movie shows Tyrannosaurus rex with his body roughly parallel to the ground and the tail that stretched behind the body to balance the head.
Like many bipedal dinosaurs, Tyrannosaurus rex was historically described as a 'living tripod', with the body at 45 degrees or less than vertical and tail dragging along the ground, similar to a kangaroo. This concept comes from the reconstruction of Joseph Leidy in 1865 Hadrosaurus, the first to describe dinosaurs in a bipedal position. In 1915, convinced that the creature stood upright, Henry Fairfield Osborn, former president of the American Museum of Natural History, further reinforced the idea of ​​launching the first complete framework of Tyrannosaurus rex compiled in this way. It stood in an upright position for 77 years, until it was demolished in 1992.
In 1970, scientists realized that this pose is incorrect and can not be defended by living animals, because it will lead to dislocation or weakening of several joints, including the hips and the articulation between the head and spine. Inaccurate AMNH mounts inspire similar portrayals in many films and paintings (such as Rudolph Zallinger's The Age of Reptiles' famous mural at the Peabody Museum of Natural History at Yale University) until the 1990s, when films like Jurassic Park introduces a more accurate posture to the general public.
Weapon Edit
When Tyrannosaurus rex was first discovered, the humerus was the only element of a known front member. For an initial pre-installed skeleton as seen by the public in 1915, Osborn was replaced again, their three-finger forelimbs from Allosaurus . A year earlier, Lawrence Lambe described a short forelimbs that had two fingers in the related part of the Gorgosaurus . It strongly suggests that Tyrannosaurus rex has the same forelimbs, but this hypothesis is not confirmed until the first complete marking of Tyrannosaurus rex was identified in 1989, belonging to MOR 555 ("Wankel" rex " ) The remains of Sue also include complete forelimbs. The arm of Tyrannosaurus rex is very small compared to the overall body size, measuring only 1 meter (3.3 feet), and some experts have called them vestigial. The bones show a large area for muscle attachment, showing considerable strength.It was recognized in early 1906 by Osborn, who speculated that the forelimbs may have been used to understand the couple during intercourse.He has also suggested that the forelimbs are used to help the animals in up from prone position.
Another possibility is that the forelimbs hold a struggling prey while it is killed by Tyrannosaurus's large jaw. This hypothesis may be supported by biomechanical analysis. Tyrannosaurus rex the front bone shows a very thick cortical bone, which has been interpreted as evidence that they were developed to withstand heavy burden. The biceps biceps muscle of an adult Tyrannosaurus rex was able to lift 199 kilograms (439 lb) by itself; Other muscles such as brachialis will work together with the biceps to make the elbow flexion even stronger. The biceps M. muscle of T.Ã, rex is 3.5 times stronger than equivalent humans. Arm arm Tyrannosaurus rex has limited range of motion, with shoulder and elbow joints allowing only 40 and 45 degree movements, respectively. In contrast, the same two joints in Deinonychus allow up to 88 and 130 degrees of motion, respectively, while the human arm can rotate 360 ​​degrees across the shoulder and move through 165 degrees at the elbow. The weight of building arm bones, muscle strength, and limited range of motion can show a system evolving to hold firm despite pressure from struggling prey animals. In the first detailed scientific description of Tyrannosaurus, paleontologist Kenneth Carpenter and Matt Smith dismissed the notion that forelimbs are useless or that Tyrannosaurus rex is a consuming liability.
According to paleontologist Steven Stanley of the University of Hawaii, about 1 meter long arm Tyrannosaurus rex is used to cut prey. Especially by teenage dinosaurs as their arms grow more slowly in proportion to their bodies and the younger Tyrannosaurus rex will have arms that are much longer than adults.
Soft-tissue Edit
In the March 2005 issue of Science Science, Mary Higby Schweitzer of North Carolina State University and colleagues announce the restoration of soft tissue from the bone marrow cavity of bone marrow from Tyrannosaurus rex . The bones are deliberate, though reluctant, broken for delivery and then not preserved in the usual way, especially since Schweitzer hopes to test it for soft tissue. Designated as Museum of the Rockies specimen 1125, or MOR 1125, dinosaurs previously excavated from Hell Creek Formation. Blood vessels are flexible, branched, and elastic but elastic bone matrix tissue is recognized. In addition, microstructures resembling blood cells are found in the matrix and blood vessels. The structure is similar to the cells and blood vessels of ostriches. Whether unknown processes, different from normal fossilizations, preserving the material, or the original material, researchers do not know it, and they are careful not to make claims about conservation. If found as an original material, any surviving protein can be used as a way to indirectly guess some of the DNA content of the dinosaurs involved, since each protein is usually made by a particular gene. The absence of prior art may be the result of a person who considers preserved tissue impossible, therefore not seeking. Since the first, two tyrannosaurs and hadrosaurs have also been found to have tissue-like structures. Research on some of the tissues involved has shown that birds are closer to relatives with tyrannosaurs than other modern animals.
In a study reported in Science in April 2007, Asara and her colleagues concluded that the seven traces of collagen proteins detected in purified Tyrannosaurus rex bone were best suited to those reported in chickens, followed by new frogs and lizards. The discovery of proteins from tens of millions of years old creatures, along with similar footprints found by teams in mastodon bones at least 160,000 years, reverses the conventional views of fossils and can divert paleontologists from bone-hunting into biochemical focus. Up to this finding, most scientists consider that fossilization replaces all living tissue with inert minerals. Paleontologist Hans Larsson of McGill University in Montreal, who is not part of the research, called the findings "a milestone," and suggested that dinosaurs could "enter the field of molecular biology and actually capture paleontology into the modern world."
Further studies in April 2008 confirmed the close relationship of Tyrannosaurus rex with modern birds. Postdoctoral biochemist Chris Organ at Harvard University announced, "With more data, they may be able to place T.Ã, rex on the evolutionary tree between crocodiles and chickens and ostriches." Co-author John M. Asara added, "We also show that the group is better with birds than modern reptiles, such as crocodiles and green anole lizards."
The soft tissue is allegedly questioned by Thomas Kaye of the University of Washington and his co-authors in 2008. They argue that what is really inside the tyrannosaur bone is a slimy biofilm made by bacteria lining the void that once occupied by blood vessels and cells. The researchers found that what had previously been identified as the remnants of blood cells, due to the presence of iron, is actually a framboid, iron-containing microscopic mineral ball. They found similar balls in various other fossils from different periods, including ammonites. In Amon, they find the ball in the place where the iron it contains has no relation to the presence of blood. Schweitzer strongly criticized Kaye's claims and argued that no evidence was reported that biofilms could produce branched, empty tubes as recorded in his studies. San Antonio, Schweitzer and colleagues published an analysis in 2011 on collagen parts that have been found, finding that the inside of the collagen coils that have been preserved, as expected from a long period of protein degradation. Other studies challenged the identification of soft tissue as a biofilm and confirmed finding "branched, structurally like vessels" from within the stony bone.
Thermoregulation Edit
In 2014, it is unclear whether
The oxygen isotope ratio in fossil bone is sometimes used to determine the temperature at which bone is deposited, since the ratio between certain isotopes is correlated with temperature. In one specimen, the isotope ratio in the bones of different parts of the body shows a temperature difference of no more than 4 to 5 Â ° C (7 to 9 Â ° F) between the trunk vertebrae and the lower leg tibia.. This small temperature range between the body core and extremities is claimed by paleontologist Reese Barrick and geoschemist William Showers to show that Tyrannosaurus rex maintains a constant internal body temperature (homeothermy) and that it enjoys metabolism somewhere between reptiles ectothermic and endothermic mammals. Other scientists have pointed out that the oxygen isotope ratios in fossils today do not always represent the same ratios in the past, and may have been altered during or after fossilization (diagenesis). Barrick and Rain have defended their conclusions in the next paper, finding similar results in other theropod dinosaurs from different continents and tens of millions of years earlier ( Giganotosaurus ). Ornithischian dinosaurs also show homeothermy evidence, while varanoid lizards of the same formation are not. Even if Tyrannosaurus rex shows homeothermy evidence, it does not mean that it is endothermic. Such thermoregulation can also be explained by gigantothermy, as in some living sea turtles.
Traces Edit
Two isolated fossil tracks have been temporarily assigned to Tyrannosaurus rex . The first was discovered at Philmont Scout Ranch, New Mexico, in 1983 by the American geologist Charles Pillmore. Originally thought to belong to a hadrosaurid, the footprint examination revealed a large unknown 'heel' in an ornithopod dinosaur track, and a trace of what may have been hallux, the fourth digit of a tyrannosaur-like leg dewclaw. The trail was published as ichnogenus Tyrannosauripus pillmorei in 1994, by Martin Lockley and Adrian Hunt. Lockley and Hunt suggest that it is most likely that the path is made by Tyrannosaurus rex , which will make it the first known trace of this species. The track was made in what was once a vegetated wetland mud. Its size is 83 cm (33 inches) in length 71 centimeters (28 inches).
The second trace possible by Tyrannosaurus was first reported in 2007 by British paleontologist Phil Manning of Hell Creek Formation of Montana. The second track is 72 cm (28 inches) long, shorter than the track described by Lockley and Hunt. Whether the traces were made by Tyrannosaurus is unclear, although Tyrannosaurus and Nanotyrannus are the only large theropods known to exist in the Hell Creek Establishment.
A set of footprints in Glenrock, Wyoming dating to the final stage of Cretaceous Maastrichtian and summoning from the Lance Formation depicted by Scott Persons, Phil Currie et al. in January 2016, and is believed to belong to either the Tyrannosaurus rex teen or the tyrannosaurid genus dubious Nanotyrannus lancensis . From measurements and based on footprint positions, the animal is believed to travel at a walking speed of about 2.8 to 5 miles per hour and is estimated to have a 1.56 m (5.1 m) to 2.06 m (6.8 ft ). A follow-up paper appears in 2017, increasing the estimated speed by 50-80%.
Locomotion Edit
There are two main problems with locomotive capabilities of Tyrannosaurus: how well it can change; and what is the maximum straight line speed. Both are relevant to the debate about whether it is a hunter or a scavenger.
Tyrannosaurus may be slow to change, it may take one to two seconds to change just 45 Â ° - a human, vertically oriented and tailed amount, can spin in a fraction of a second. The cause of the difficulty is rotational inertia, as most of the transiosaurus mass is some distance away from its center of gravity, as humans carry heavy wood horizontally - though that may have reduced the mean distance by arching its back and tail and pulling its head and the front legs close to his body, somewhat like the way the ice skaters drag their arms closer in order to spin faster.
Scientists have produced various estimates of maximum speed, mostly about 11 meters per second (40 km/h, 25 mph), but some as low as 5-11 meters per second (18-40 km/h; 11-25 mph), and some as high as 20 meters per second (72 km/h; 45 mph). Researchers have to rely on various estimating techniques because, while there are many traces of a very large theropod walk, so far nothing has been found from the very large theropods running - and this absence may indicate that they are not running. Scientists who think that Tyrannosaurus can run show that hollow bones and other features that will lighten the body may have held adult weight to just 4.5 metric tons (5.0 ton short) or more, or that other animals such as ostriches and horses with long and flexible legs can reach high speeds through slower but longer steps. Some people also argue that Tyrannosaurus has a leg muscle that is relatively larger than any living animal today, which can allow a fast run at 40-70 kilometers per hour (25-43 mph).
Jack Horner and Don Lessem argued in 1993 that Tyrannosaurus was slow and may not work (no air phase in mid-step), because the ratio of the femur (thigh bone) to the tibia (tibia) bone is more large from 1, as in most large theropods and like modern elephants. Holtz (1998) notes that tyrannosaurids and some closely related groups have much longer distal hindlimb components (shin plus leg plus feet) relative to the length of the femur than most other theropods, and that tyrannosaurids and their close relatives have a closely related metatarsus that is more effective sending locomotive forces from foot to lower leg than in previous theropods ("metatarsus" means leg bone, which functions as part of the foot in digitigrade animals). He therefore concluded that tyrannosaurids and their close relatives were the fastest large theropods. Thomas Holtz Jr. echoing this sentiment in its 2013 lecture, stating that the giant allosaurs had shorter legs for the same body size than Tyrannosaurus, while Tyrannosaurus had a longer, thinner, and more. legs interlocked for the same body size; animal attributes that move faster.
A study by Eric Snively and Anthony P. Russell published in 2003 also found that tctannosaurid arctometatarsals and elastic ligaments work together in what he calls the 'tensile keystone model' to reinforce Tyrannosaurus foot, improves animal stability and adding greater resistance to dissociation to other theropod families; while still allowing the opposite resistance to be reduced in ratite, horse, giraffe and other animals by metapodia to a single element. The study also showed that elastic ligaments in larger vertebrates can store and restore relatively more elastic strain energy, which can improve locomotor efficiency and decrease strain energy transferred to bone. This study suggests that these mechanisms can work efficiently in tyrannosaurids as well. Therefore, this study involves identifying the types of ligaments attached to the metatarsals, then how they function together and comparing them with other modern theropods and analogs. The scientists found that arctometatarsals may have activated tyrannosaurid legs to absorb forces such as linear slowing, lateral acceleration and torque more effectively than other theropods. It is also stated in their research that this may imply, though not necessarily, that tyrannosaurids such as Tyrannosaurus have greater agility than other large theropods without arctometatarsus.
Christiansen (1998) estimates that the foot bones of Tyrannosaurus are not significantly stronger than elephants, which are relatively limited in their highest speed and never actually run (no air phase), and hence it is proposed that speed The maximum dinosaur is about 11 meters per second (40 km/h, 25 mph), which is the speed of a human sprinter. But he also notes that these estimates depend on many doubtful assumptions.
Farlow and colleagues (1995) argue that Tyrannosaurus weighing 5.4 metric tons (6.0 tonnes) to 7.3 metric tons (8.0 tonnes short) will be critical or even injured fatal if it falls as it moves quickly, because its body will hit the ground at a slowing 6Ã, g (six times the acceleration due to gravity, or about 60 meters/sÃ,²) and the tiny arm can not reduce its impact. Giraffes have been known to roam at 50 kilometers per hour (31 mph), despite the risk that they may break legs or worse, which can be fatal even in a safe environment such as a zoo. Thus it is possible that Tyrannosaurus is also moving fast when necessary and should accept the risk.
In another study, Gregory S. Paul points out that adult knees and butterflies that are weakened by Tyrannosaurus are much better adapted for running than elephants or humans, indicating that Tyrannosaurus has a large Bone the ilium and the cnemial emblem that will support the large muscles needed to run. He also mentions that Alexander's (1989) formula for calculating speed with bone strength is only partly reliable. He suggested that the formula is too sensitive to bone length; making long bones artificially weak. He also pointed out that the low risk of injury in combat might be worth the risk of Tyrannosaurus falling while running.
Recent research on Tyrannosaurus propulsion does not support speeds faster than 40 kilometers per hour (25 mph), ie medium speed. For example, a 2002 paper in Nature uses a mathematical model (validated by applying it to three living animals, crocodiles, chickens, and humans, then eight other species including emus and ostriches) to measure the leg muscles of the mass which is needed to run fast (more than 40 km/h or 25 mph). They found that the proposed top speed of more than 40 kilometers per hour (25 mph) was not feasible, as they would require very large leg muscles (more than about 40-86% of the total body mass). Even a fairly fast speed will require great leg muscles. This discussion is difficult to solve, because it is not known how big the leg muscles actually are in Tyrannosaurus . If they are smaller, only 18 kilometers per hour (11 mph) walk or jogging may be possible.
A 2007 study used a computer model to estimate the running speed, based on data taken directly from the fossil, and claimed that Tyrannosaurus rex had the highest running speed of 8 meters per second (29 km/h, 18 mph) ). Professional soccer players (soccer) on average will be a little slower, while human sprinters can reach 12 meters per second (43 km/h; 27 mph). This computer model predicts a top speed of 17.8 meters per second (64 km/h, 40 mph) for 3 kilograms (6.6 lb) Compsognathus (probably a teenager).
In 2010, Scott Persons, a graduate student from the University of Alberta, proposed that the speed of Tyrannosaurus might have been enhanced by strong tail muscles. He finds theropods like T. rex having different muscle settings different from modern birds and mammals but with some similarities to modern reptiles. He concluded that caudofemoralis muscles connecting the coccyx and upper leg bones could help Tyrannosaurus in the withdrawal and improve the ability to run, its agility and balance. Caudofemoralis muscle will become the key muscle in femoral retraction; pulled back the legs on the femur. The study also found that theropod skeletons such as Tyrannosaurus have adaptations (such as increased transverse processes in the spine) to allow for greater tail muscle growth and Tyrannosaurus's tail muscle mass may have been underestimated by more than 25 percent and possibly as much as 45 percent. Caudofemoralis muscle was found to consist of 58 percent of muscle mass in Tyrannosaurus tail . Tyrannosaurus also has the largest absolute and relative caudofemoral muscle mass of the three extinct organisms in this study. This is because Tyrannosaurus also has an additional adaptation to activate the large tail muscle; elongation of the tail bend. According to People, an increase in tail muscle mass will move the center of the mass closer to the back and hips which will reduce the tension in the leg muscles to support its weight; improve balance and agility as a whole. It will also make this animal less heavy in front, thus reducing rotational inertia. People also note that the tail is also rich in tendons and septa that can store elastic energy, and thus improve the efficiency of locomotives. People add that this means the non-avian theropod actually has a wider tail than previously described, as broad or wider laterally than the dorsoventral near the base.
Heinrich Mallison of the Berlin Museum of Natural History also presented a theory in 2011, which showed that Tyrannosaurus and many other dinosaurs may have reached relatively high speeds through short, fast steps rather than the long steps used by birds and modern mammals. while running, equating their movements to walk with power. This, according to Mallison, will be achievable regardless of joint strength and reduce the need for additional muscle mass in the legs, especially in the ankles. To support his theory, Mallison assessed the limbs of various dinosaurs and found that they differ from modern mammals and birds; have their stride length greatly limited by their skeleton, but also have relatively large muscles on the back. He found some similarities between the muscles of dinosaurs and pedestrians; have less muscle mass in the ankle but more on the back. John Hutchinson suggested warnings about this theory, suggesting that they must first look into the muscles of dinosaurs to see how often they can be infected.
A study in July 2017 by a team of researchers led by William Sellers of Manchester University found that an adult Tyrannosaurus could not run because of a very high skeletal load. This study uses the latest computational technology to test its findings. The researchers used two different structural mechanical systems to create computer models. The weight they settled for their calculations was a conservative estimate of 7 tons. This model indicates that speeds above 11 mph (18 km/h) may destroy the leg bones of Tyrannosaurus . This finding may mean that running is also impossible for other giant theropod dinosaurs such as Giganotosaurus , Mapusaurus and Acrocanthosaurus .
Another study in July 2017 by researchers from the German Center for Biodiversity Research (iDiv) found that the top speed of Tyrannosaurus was about 17 mph (27 km/h). Other dinosaurs including Triceratops , Velociraptor and Brachiosaurus are also analyzed in this study, as do many living animals such as elephants, cheetahs and rabbits. The speed of Tyrannosaurus is calculated by factoring the weight in relation to the medium in which it travels (in the case of theropods, soils) and with the assumption that: one; animals reach their maximum speed during relatively short sprints, and two; Newton's laws of motion dictate that the masses must overcome inertia. It was found that large animals such as Tyrannosaurus spent their energy reserves long before they reached their theoretical peak velocity, resulting in a parabolic-like relationship between size and speed. This equation can calculate the animal's top speed with an accuracy of almost 90% and can be applied to live and extinct animals.
Those who argued that Tyrannosaurus could not run predicted the top speed of Tyrannosaurus about 17 kilometers per hour (11 mph). It is still faster than the most probable prey species, hadrosaurid and ceratopsia. In addition, some proponents of the notion that Tyrannosaurus is a predator claim that the tyrannosaur flight speed is not important, because it may be slow but still faster than the likelihood of its prey. Thomas Holtz also notes that Tyrannosaurus is proportionately longer than the animals being hunted: duck-billed dinosaurs and horned dinosaurs. Paul and Christiansen (2000) argue that at least ceratopsia later has an erect forelimbs and larger species may be as fast as rhinoceros. Healing Tyrannosaurus wound bites on ceratopsian fossils is defined as evidence of attacks on live ceratopsia (see below). If ceratopsia coexist with rapid Tyrannosaurus , it raises doubts on the argument that Tyrannosaurus does not have to be quick to catch its prey.
Brain and senses Edit
A study conducted by Lawrence Witmer and Ryan Ridgely of Ohio University found that Tyrannosaurus shared the increased sensory capability of other coelurosaurs, highlighting relatively quick and coordinated eye and head movements, as well as enhanced ability to feel inferior the frequency sounds that allow tyrannosaurs to track the movement of prey from a distance and an increased sense of smell. A study published by Kent Stevens of the University of Oregon concluded that Tyrannosaurus had a sharp vision. By applying a perimetric modification to the facial reconstruction of several dinosaurs including Tyrannosaurus , the study found that Tyrannosaurus has a 55 degree range of binoculars, more than modern eagles, and has 13 times human visual acuity, so it goes beyond the visual acuity of an eagle that is only 3.6 times that of a person. This will allow Tyrannosaurus to distinguish objects as far as 6 km (3.7 mi), which is larger than 1.6 km (1 mi) that can be seen by humans.
Thomas Holtz Jr. will note that the high depth perception of Tyrannosaurus may be due to prey to be hunted; noting that it should hunt for horned dinosaurs such as Triceratops , armored dinosaurs such as Ankylosaurus and duck-ducked dinosaurs may have complex social behavior. He will suggest that this makes the more crucial accuracy for the Tyrannosaurus that allows it, "go in, get the punch and release." In contrast, Acrocanthosaurus has a limited depth of perception as they hunt for large sauropods, which are relatively rare during Tyrannosaurus time.
Tyrannosaurus has a very large olfactory odor and olfactory nerves associated with the size of their brain, the organ responsible for high olfactory. This suggests that the sense of smell is highly developed, and implies that tyrannosaurs can detect carcasses with scents alone at great distances. The sense of smell in tyrannosaurs may be comparable to that of modern vultures, who use the scent to track carcasses to scavenge. The study of olfactory tubes shows that Tyrannosaurus rex has the smell of 21 of the most advanced non-avian species.
Somewhat unusually among theropods, T.Ã, rex has a very long cochlea. Cochlear length is often associated with auditory acuity, or at least the importance of hearing in behavior, implying that hearing is a very important feeling for tyrannosaurs. Specifically, the data show that Tyrannosaurus rex is best heard in low frequency ranges, and that low-frequency sounds are an important part of the behavior of tyrannosaurs.
A study by Grant R. Hurlburt
Source of the article : Wikipedia
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