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The Tyrannosaurus "Stan" in the Manchester Museum

The Tyrannosaurus "Stan" in the Manchester Museum

Temporal occurrence
Upper Cretaceous (Upper Maastrichtian )
68 to 66 million years
Lizard dinosaur (Saurischia)
Scientific name
Osborn , 1905
  • Tyrannosaurus rex

Tyrannosaurus ( Latinization from ancient Greek τύραννος týrannos or Latin tyrannus ["king, despot"] and σαῦρος sauros ["lizard"]) is a genus of carnivorous dinosaurs from the Theropoda group .

The only generally recognized species is Tyrannosaurus rex , often abbreviated to T. rex , colloquially also T-rex . As the most famous dinosaur, this species is an integral part of popular culture. However, some paleontologists consider Tarbosaurus bataar from Asia to be a second species. Various other genera of North American tyrannosaurids have also been described as synonyms of Tyrannosaurus .

Tyrannosaurus fossils were found in various rock formations in western North America , which are dated to the last three million years of the Cretaceous , that is, about 68 to 66 million years ago (late Maastrichtian ). Tyrannosaurus was one of the last non-avian dinosaurs that existed until the Cretaceous Tertiary mass extinction .

Like other tyrannosaurids, the tyrannosaurus was a bipedal (two-legged) carnivore with a massive skull, which was balanced by a long, heavy tail. Tyrannosaurus rex's arms were small in relation to its long and strong hind legs , but unusually strong for its size. They only showed two fingers, although a possible rudimentary (regressed) third finger has been reported. With a length of up to 13 meters, a waist height of four meters and a weight of up to 9 tons, it was the largest known tyrannosaurid and one of the largest land-dwelling carnivores ever, although some other theropods were similar in size or even larger. By far the largest carnivore in its habitat, Tyrannosaurus was perhaps at the top of the food chain as a top predator , hunting hadrosaurs and ceratopsians ; however, some experts suspect that it was primarily a scavenger .

To date, more than 30 specimens of Tyrannosaurus have been identified, including some near-complete skeletons. Soft tissue and proteins have been described from at least one of these findings. The comparatively large number of finds made it possible to study the biology of this animal, including individual development and biomechanics . Also up for discussion are the feeding habits, physiology and possible speed of Tyrannosaurus .


Size comparison of selected large theropods, Tyrannosaurus rex is shown in green (far right)
Different specimens of Tyrannosaurus rex compared to a human
Live reconstruction

Tyrannosaurus was one of the largest land-dwelling carnivores of all time. The largest and heaviest known specimen is the Canadian "Scotty" find (catalog number RSM P2523.8), which reached dimensions of a good 13 meters and a weight of almost 9 tons. The find thus exceeds the largest almost complete specimen " Sue " (catalog number FMNH PR2081), which measures between 12.29 and 12.4 meters in length and has a hip height of 4 meters. Weight estimates by various scientists vary considerably, ranging from less than 4.5 to over 7.2 tons, with the most recent estimates being between 5.4 and 6.8 tons. However, a new method measured the volume of some individuals and resulted in a minimum of 9.5 t for “Sue”. Greg Paul estimates “Sue” at 6.1 t.

Tyrannosaurus rex was larger than the well-known Allosaurus from the Upper Jurassic and slightly smaller than Spinosaurus from the early Upper Cretaceous. Its weight exceeds that of all other terrestrial theropods - only Spinosaurus could have reached similar weight.

The "S" -shaped neck of the Tyrannosaurus was short and muscular to support the heavy head. The legs were among the longest of all theropods in relation to the body and are in contrast to the tiny but powerful arms. For a long time it was assumed that the arms only had two fingers - in a report that has not yet been published, however, a third, rudimentary finger is described. The tail was heavy and long to balance the massive torso and head, and sometimes showed over forty vertebrae. To compensate for the enormous mass of the animal, many of the bones were hollow.

The largest known Tyrannosaurus skulls were up to 1.5 meters long. In contrast to the skulls of other non-tyrannosauroid theropods, the back of the skull was extremely wide while the snout was narrow. As a result of this adaptation, the eyes were directed more forward, which enabled unusually good spatial vision . The skull bones were massive and some bones, such as the paired nasal bone, were fused together, which stabilized the skull. Many bones, however, were pneumatic, showing cavities that made the bones more flexible but also lighter. These and other features that strengthened the skull were part of a trend within the tyrannosaurids that resulted in an increasingly powerful bite that far surpassed other non-tyrannosaurids. The upper jaws were “U” -shaped when viewed from above, and not “V” -shaped, as in most other non-tyrannosauroid theropods. While this increased the amount of tissue a tyrannosaur could tear out of its prey with one bite, it also increased the strain on the front teeth.

The teeth of Tyrannosaurus and other tyrannosauroids showed heterodontia (differences in shape). The teeth of the intermaxillary bone at the front end of the upper jaw were tightly packed, “D” -shaped in cross-section, had reinforcing ridges on the back, were incisiform (the tips were shaped like a chisel) and curved backwards. The “D” -shaped cross-section, reinforcing ridges, and back curvature reduced the risk of teeth kinking during the bite. The rest of the teeth were sturdy, banana-shaped, and more spaced apart; they too had reinforcing combs. The teeth of the upper jaw were larger than the teeth of the lower jaw, with the exception of the teeth at the rear of the lower jaw. The largest tooth found, including the tooth root, is estimated to be 30 cm long; this makes it the largest tooth known to date from a carnivorous dinosaur.


A tyrannosaurus skull (AMNH 5027)

Tyrannosaurus is the type genus of the superfamily Tyrannosauroidea , the family Tyrannosauridae and the subfamily Tyrannosaurinae - in other words, it is the standard by which paleontologists decide whether other species are to be classified in the same group. Other members of the subfamily Tyrannosaurinae include the North American Daspletosaurus and the Asian Tarbosaurus , both of which have been considered synonyms of Tyrannosaurus by some researchers in the past . It used to be believed that the tyrannosaurids were the descendants of earlier groups of large theropods, such as the megalosaurs and the carnosaurs . Today they are classified within the Coelurosauria , whose members were mostly characterized by a small body size.

In 1955, Soviet paleontologist Evgeny Maleev named a new species, Tyrannosaurus bataar , discovered in Mongolia . In 1965 it was renamed Tarbosaurus bataar and thus assigned to its own genus. Despite this renaming, many phylogenetic analyzes came to the conclusion that Tarbosaurus bataar was the sister taxon of Tyrannosaurus rex , which is why it was often listed as an Asian Tyrannosaurus species. A re-description of the skull of Tarbosaurus bataar showed, however, that it was much narrower than that of Tyrannosaurus rex and that the forces during a bite were distributed quite differently on the skull bones. The distribution of forces in the skull of Tarbosaurus bataar was rather similar to that of Alioramus , another Asian tyrannosaur. A cladistic analysis concluded that Alioramus , rather than Tyrannosaurus , was the sister taxon of Tarbosaurus - if this can be confirmed, it would mean that Tarbosaurus and Tyrannosaurus should be kept separately.

Other tyrannosaurid remains found in the same geological formations as Tyrannosaurus rex were originally thought to be separate taxa - including Aublysodon and Albertosaurus megagracilis , the latter being renamed Dinotyrannus megagracilis in 1995 . Today these finds are listed as juvenile specimens of Tyrannosaurus rex .


A skull discovered in Montana, only 60 cm long, was originally described by Charles W. Gilmore in 1946 as Gorgosaurus lancensis, but was later assigned to a new genus, Nanotyrannus . In 2001, a group of researchers from the Burpee Museum of Natural History discovered another skeleton that was 50% intact and was nicknamed "Jane" (catalog number BMRP 2002.4.1.). Opinions on the validity of N. lancensis are divided. Many paleontologists attribute the findings to a juvenile T. rex . A study published in Science Advances in 2020 supports this assumption: a detailed analysis of cross-section bones of juvenile Tyrannosaurus suggests that Tyrannosaurus growth rates varied with age, and that the species appeared to be able to slow its growth when food was scarce, which might make them uncomfortable evolutionary advantage. Some of the Nanotyrannus bones examined in this way confirmed that they were indeed juveniles. Nanotyrannus was either larger than previously thought, or - what the researchers believe is much more likely - the fossils belong to young tyrannosaurus . The taxon Nanotyrannus would therefore be invalid.


The type specimen of T. rex at the Carnegie Museum of Natural History . This skull was heavily repaired, using Allosaurus as a template.

The first find that can be ascribed to Tyrannosaurus rex consists of two partial vertebrae (one of which has been lost) found by Edward Drinker Cope in 1892 and described as Manospondylus gigas . Osborn recognized the similarity between M. gigas and T. rex as early as 1917, but could not explain both genera to be identical, as the manospondylus vertebrae were too fragmentary.

In June 2000, the Black Hills Institute located the site of M. gigas in South Dakota and uncovered more tyrannosaur bones. These have been described as further remains of the same individual and recognized as identical to Tyrannosaurus rex . According to the International Rules for Zoological Nomenclature (ICZN), according to which the naming of animals is regulated internationally, Manospondylus gigas should have priority over Tyrannosaurus rex because it was named before T. rex . However, the fourth edition of the ICZN, which came into force on January 1, 2000, states that the predominant name must be retained if the previously named synonym is no longer used as a valid name since 1899 and the later named synonym as a valid name in at least 25 Work has been carried out that has been published by at least ten authors in the previous 50 years. Tyrannosaurus rex fulfills these conditions and would likely, if ever challenged, be listed as a noun protectum ("protected name").


Developmental and Population Biology

A graph showing the putative growth curves (body mass versus age) for four tyrannosaurids; Tyrannosaurus is shown in black (after Erickson et al., 2004)

By discovering some juvenile Tyrannosaurus rex specimens, scientists were able to draw conclusions about individual development ( ontogenesis ), life expectancy and growth rates . The smallest known individual ( LACM 28471, the "Jordan Theropod") is estimated to weigh only 29.9 kg, while the largest specimens, such as RSM P2523.8 ("Scotty"), probably weighed over 8800 kg. Histological analyzes came to the conclusion that LACM 28471 was only two years old when it died, while “Scotty” was 30 years old, which is perhaps close to the maximum age of the species.

Other specimens were also examined bone histologically. In this way, growth curves could be developed that relate the age of an individual to his or her size. The growth curve of T. rex is "S" -shaped and shows that young animals did not exceed a weight of 1800 kg until they were around 14 years old, when a rapid growth phase began. During this four-year growth phase, a young T. rex would have gained an average of 600 kg per year. At 18, the curve flattens out again, indicating a dramatic slowdown in growth over a short period of time. For example, there is only 600 kg between the 28-year-old “Sue” and the 22-year-old Canadian ( RTMP 81.12.1). Another study published in 2004 supports these results and found that rapid growth began to slow at the age of 16. This sudden slowdown in growth could indicate reaching sexual maturity. This hypothesis is supported by the discovery of a calcium-rich bone substance in the thigh bone (femur) of a 16 to 20 year old T. rex from Montana ( MOR 1125, also known as "B-rex") - this bone substance is otherwise only known from female birds that stand in front of the egg-laying and need the calcium to form the eggshells. This indicates that “B-rex” was sexually mature . A new study indicates an age of 18 years for this specimen. Other tyrannosaurids show very similar growth curves, but had lower growth rates because they did not grow as large as T. rex .

More than half of known T. rex specimens died within six years of reaching sexual maturity; a pattern found in other tyrannosaurs and in some of today's large birds and mammals. These species are characterized by a high death rate as "babies" followed by a relatively low death rate as young animals. After sexual maturity, the death rate rises again, in part because of the stresses and strains of reproduction. One study suggests that the rarity of juvenile T. rex fossils is in part due to the low death rate of young animals; the young did not die in large numbers and therefore rarely fossilized . However, this rarity can also have other causes, such as an incomplete fossil record or the preference given by fossil collectors to large, spectacular finds over small ones.

Gender dimorphism

Tyrannosaurus skeleton casts in mating position in the Jurassic Museum of Asturies

Two different types, or "morphs," similar to some other theropods have been described based on differences in skeletal construction. The so-called "robust morph" was built heavier than the other type, known as the "graceful morph". Usually these morphological differences are interpreted as gender dimorphism , with the "robust" individuals mostly interpreted as females. For example, the pelvis of some "robust" skeletons appears to be wider, perhaps to allow the eggs to pass through. The robust morph was also believed to be associated with a reduction in the size of the chevron bone on the first caudal vertebra, which should also have allowed the passage of the eggs - something similar has been wrongly described in crocodiles.

In recent years, doubts have arisen as to whether these traits are actually gender dimorphism. As a study from 2005 shows, crocodiles do not show sex dimorphism on the chevron bones, although this was previously suspected. Thus, the assumed sexual dimorphism on the chevron bones of T. rex also appears questionable. The well-developed chevron bone of the first caudal vertebra of "Sue", a very robust individual, ultimately shows that this feature cannot be used to distinguish the two morphs. Since skeletons of T. rex of Saskatchewan (Canada) to New Mexico were found, these differences could also be geographic variations between individuals, and no sexual dimorphism. The differences could also be related to age, with robust individuals representing older animals.

Only a single T. rex skeleton could be conclusively assigned to a gender. Soft tissue has been preserved in some of the bones of "B-rex", and calcium-rich tissue was also discovered, which otherwise only grows in today's female birds during egg-laying and is required for the formation of eggshells. This tissue is absent in male birds, although they can produce it when given sex hormones such as estrogen . This leads to the conclusion that “B-rex” is a female. Further research has shown that this calcium-rich tissue is absent in crocodiles, which - along with birds - are considered to be the closest living relatives of the dinosaurs. This is another indication of the close relationship between birds and dinosaurs.


Outdated reconstruction (by Charles R. Knight ) showing T. rex in an upright posture
Model at the Senckenberg Natural History Museum ; the attitude corresponds to the current knowledge

How many bipedal current ( bipede ) dinosaur was also T. rex in the past often presented in an upright position, with the tail as a third leg rested on the floor and had or less inclined the axis of the body from the vertical position of 45 degrees, similar to with a kangaroo . This concept comes from Joseph Leidy's reconstruction of a Hadrosaurus from 1865, the first reconstruction of a dinosaur in a bipedal position. Henry Fairfield Osborn , former President of the American Museum of Natural History (AMNH) in New York , unveiled an erect assembly of the first complete T. rex skeleton in 1915, in support of the erect posture hypothesis. The skeleton stood in this upright position for nearly a century until it was dismantled in 1992. By 1970, scientists noticed that this attitude was incorrect; an upright posture would have led to the displacement of various joints, such as the hips and the connection between the head and the spine. Despite these inconsistencies, the skeleton in the AMNH inspired similar representations in many films and paintings (such as Rudolph Zallinger's famous mural “The Age Of Reptiles” in the Peabody Museum of Natural History ) well into the 1990s when films such as Jurassic Park popularized a more correct posture. Modern depictions show T. rex holding his body roughly parallel to the ground while the tail balanced his head.


Close up of the arms of a T. rex skeleton in the National Museum of Natural History , Washington, DC

Initially, only the humerus was known of the arms , which is why Osborn modeled longer, three-fingered arms that resembled those of Allosaurus for the first assembled Tyrannosaurus skeleton on display from 1915 . As early as 1914, however , Lawrence Lambe described the short, two-fingered arms of the closely related Gorgosaurus , which suggested similar arms in T. rex . This assumption could only be confirmed in 1989 when complete arms were found with MOR 555 (the "Wankel rex"). The skeleton of "Sue" also shows full arms. T. rex's arms were only one meter long in relation to their height. Nevertheless, they were not regressed ( rudimentary ), but had large attachment surfaces for muscles, which shows that they were very strong. This was already noticed by Osborn in 1906, who speculated that the arms could have been used to hold the partner in place during copulation . Another author suspects that the arms might have supported the animal when it rose from the prone position. Another option was to hold on to prey so that the enormous jaws of the tyrannosaur could take care of them. This hypothesis could be supported by biomechanical studies: For example, the arm bones show an extremely thick cortex (the hard outer bone ), which shows that they could withstand heavy loads. The biceps brachii of a full-grown Tyrannosaurus rex could lift approx. 200 kg on its own, in interaction with other muscles it would be even stronger. However, the shoulder and elbow joints only allowed movements of 40 to 45 degrees - in contrast, Deinonychus could move his arms by 88 to 130 degrees, while a human arm could move 360 ​​degrees at the shoulder and 165 degrees at the elbow joint. According to some researchers, the heavy structure of the arm bones, the extreme strength of the muscles and the limited range of motion indicate a system that was designed to hold prey.

Soft fabric

In March 2005, researchers around Mary Schweitzer announced that soft tissue had been discovered in the medullary cavity of a 68 million year old leg bone of Tyrannosaurus . The bone had to be broken for transport and then was not subjected to the usual preservation procedure because Schweitzer hoped to be able to test it for soft tissue. The bone (MOR 1125) from the Museum of the Rockies was previously excavated in the Hell Creek Formation . The researchers found flexible, bifurcating blood vessels and fibrous but elastic bone tissue. In addition, microstructures were found in these vessels and tissues that resemble blood cells, the structures being similar to the blood cells and vessels of ostriches. Whether the material was preserved through an unknown process different from normal fossilization , or whether it is original material, is unknown. If the material is original, part of the DNA sequence could be inferred indirectly with the help of preserved proteins, since each protein is produced by a special gene. The fact that soft tissue was not discovered earlier in the bones of dinosaurs could be due to the fact that researchers believed that soft tissue that has survived to this day was excluded and therefore did not look for it. Since this discovery, tissue-like structures have been found in two other tyrannosaurs and one hadrosaur. A later study found traces of the structural protein collagen in a purified Tyrannosaurus bone. These studies of ancient tissue from tyrannosaurs confirm that birds are more closely related to tyrannosaurs than to other modern animals.

In the 2007 study by Chris Organ, a biologist at Harvard University, and John Asara from the Beth Israel Deaconess Medical Center, they were able to establish a relatively safe phylogenetic relationship using six peptides with 89 amino acids in the thigh bone found by Mary Schweitzer between alligators and chickens and ostriches. Accordingly, the chickens' first split off are the closest living relatives of the T. rex. This method was tested on the basis of the relationship between the mastodon and the elephant. The class of birds is divided into primitive jaws (Palaeognathae) and new jaws (Neognathae). The class of the primitive pine birds has largely died out and has only survived in six families. These are divided into ratites (Struthioniformes) such as the ostrich and cockroaches (Tinamiformes). Are u. a. the elephant bird families of Madagascar and the moas of New Zealand.

Thomas Kaye and colleagues question these results in a publication published in 2008 and believe that the alleged tissue remains are bacterial biofilms . The bacteria once colonized the cavities in the bone that were previously occupied by real blood vessels and cells. The researchers also interpret the structures that Schweitzer interpreted as blood vessels due to their iron content as framboids - rounded, microscopic mineral structures. The researchers found such structures in other fossils, including an ammonite in a place where the iron found could not have had anything to do with blood.

Skin and feathers

In 2004 the early tyrannosauroid Dilong paradoxus from the famous Yixian Formation was described by China. As with many other theropods of this formation, fiber-like structures are visible on the Dilong skeleton , usually interpreted as the precursors of feathers. There have been speculations that tyrannosaurs and other tyrannosaurids could have had such protofeathers too - but rare skin prints from adult tyrannosaurids from Canada and Mongolia show scales typical of other dinosaurs. It is possible that proto-feathers covered the parts of the body that have not been passed down through skin prints. However, the lack of insulating body covering is also evident in today's large mammals such as elephants , hippos and rhinos . Large bodies can store heat much better than small ones, as the volume increases faster than the surface of the skin with increasing size. An insulating fur or plumage is no longer an advantage for large animals in warm climates and can even become a disadvantage, as there is a risk of overheating. Proto-feathers are likely lost during the evolution of large tyrannosaurids like Tyrannosaurus .


Live reconstruction of a Tyrannosaurus rex with a captured Triceratops

As with many other large carnivorous dinosaurs, there is disagreement as to whether the Tyrannosaurus was an active hunter or a scavenger.

Available bite marks on fossil bones (sometimes even on other Tyrannosaurus bones themselves), its huge teeth and large jaws seem to speak for the role of a hunter. David Burnham from the University of Kansas explains this in a recent study from 2013: During excavations, he and his colleagues found a broken tyrannosaurus tooth between the caudal vertebrae of the hadrosaur Edmontosaurus annectens . Since the vertebrae had grown together around the tooth, in his opinion it can be assumed that the T. rex pursued the fleeing prey and, as predators do today, wanted to bring it down by weakening the animal with large wounds.

The arrangement of the eyes in the skull suggests that tyrannosaurs could fixate on a target with both eyes. This characteristic is typical of hunting animals. The discovery of a well-preserved skull also made it possible to reconstruct the tyrannosaurus brain. It was found that the olfactory center was relatively large. Finds made a few years ago of other large theropods , some of which are closely related to Tyrannosaurus , also indicate that they lived in family groups, which is also a strong indicator of specialized hunting behavior. The skeletons of a young animal and an adolescent were also found in "Sue", the largest specimen of a Tyrannosaurus rex found to date .

Other scientists, however, disagree with the role of the active hunter. In their opinion, Tyrannosaurus was a scavenger that fed on animals that had already died. Its size and strength would also have allowed it to hunt down smaller carnivores for their prey. One of the best-known proponents of this theory is the paleontologist Jack Horner , who also advised Steven Spielberg on his film Jurassic Park in the 1990s . He relies on the anatomy of the Tyrannosaurus rex :

  • The arms of the Tyrannosaurus rex are said to be unsuitable for a hunter. If he had fallen while running, his little arms would not have been able to catch him and getting up again would have cost a lot of strength.
  • The teeth of the Tyrannosaurus rex are not blade-shaped like those of predatory dinosaurs, but rounded. According to Horner, this suggests that the teeth were more suitable for grinding bones and cartilage.
  • The Tyrannosaurus rex's brain was not as pronounced as that of a predator. The visual center had not been optimized for a good optical detection of prey, instead the olfactory center was disproportionately large, as in scavengers. The only animal that has a proportionally larger olfactory center is the vulture . According to Horner, Tyrannosaurus rex could probably smell carrion at a distance of up to 40 km.
  • The legs of the Tyrannosaurus rex are not suitable for short sprints when hunting. The ratio of the upper to lower leg bones is not like that of sprinters. In a sprinter, the lower leg bones are longer than the thigh bones, but in Tyrannosaurus rex the ratio is reversed. Tyrannosaurus rex's legs are therefore not designed for chasing or quickly attacking prey, but for long hikes to carrion, which it could see from a great distance.

Pure scavengers are, however, rarely represented in the animal world; The vultures of the genus Gyps , for example, live exclusively on carrion and can search large areas with minimal expenditure of energy, which an animal living on the ground would not be able to do. Most recent carnivorous mammals and birds, as well as many scalloped reptiles, also eat fresh carcasses or use opportunities to hunt the prey from smaller predators .

Live reconstruction of a Tyrannosaurus rex skull in the Natural History Museum Vienna
Skull of a tyrannosaurus in the Palais de la Découverte , Paris

As controversial as the scavenger theory is the question of whether Tyrannosaurus rex was a loner or a pack animal . Jack Horner is also one of the representatives of the pack animal theory. The theory is mainly based on sites where the remains of several specimens were found. Since the remains of other dinosaurs were not found there, the explanation is excluded that these are places where many animals perished simply because of special dangers, as could be the case with swamps , moors , the feet of high cliffs or asphalt lakes . There are similar sites with the remains of other large carnivorous dinosaurs, such as Mapusaurus roseae , which are generally considered to be pack animals based on these findings.

According to a long-term study by the Universities of Liverpool and Manchester , Tyrannosaurus rex achieved a calculated bite force of 35,000 to 57,000 Newtons . In land carnivores, this power was only surpassed by the primeval crocodiles, including Deinosuchus .


Reconstruction of an infection in the oropharynx and lower jaw area from MOR 980 ("Pecks Rex")

Tyrannosaurus and other tyrannosaurid fossils often show changes on one side or both sides of the lower jaw , smooth-edged, erosive lesions that run through the entire thickness of the bone. In "Sue" these bone changes are interpreted as bite marks from internal fighting or as actinomycosis (a bacterial infection ). Investigations on ten individuals with comparable lesions prompted Wolff et al. 2009 to the alternative hypothesis that a possible cause could also be an infectious disease similar to trichomonosis , since the lesions correspond to those in today's birds, especially birds of prey , that are infected with the corresponding pathogen ( Trichomonas ). In the advanced stage, the pathological changes and the associated functional restrictions on the mouth, throat and esophagus were so significant that they very likely led to death by starvation.

Discovery story

Skeletal reconstruction by William D. Matthew from 1905, the first reconstruction of Tyrannosaurus to be published

Henry Fairfield Osborn , then President of the American Museum of Natural History , described and named Tyrannosaurus rex in 1905. The generic name derives from the Greek words τυραννος ( tyrannos - "king, tyrant, despot") and σαυρος ( sauros - "lizard") ) from. As an epithet , Osborn chose the Latin word rex , which means "king". Thus, Tyrannosaurus rex can be translated as "King King Lizard", which indicates the enormous body size and dominance of this animal over other species of its time.

Earliest finds

Model of a planned, but never completed, exhibition for the American Museum of Natural History by Henry Fairfield Osborn

Teeth, which are now ascribed to Tyrannosaurus rex , were discovered by A. Lakes near Golden in Colorado as early as 1874 . In the early 1890s, JB Hatcher collected postcranial remains in eastern Wyoming that were initially attributed to a large ornithomimus species ( Ornithomimus grandis ) but are now attributed to Tyrannosaurus rex . Fragments of the vertebrae that Edward Drinker Cope found in western South Dakota in 1892 and named Manospondylus gigas have also been reclassified as Tyrannosaurus rex .

Barnum Brown discovered the first partial skeleton of a Tyrannosaurus rex in 1900 in eastern Wyoming. Brown found another skeleton in 1902 in the Hell Creek Formation in Montana . Henry Fairfield Osborn described both skeletons in the same publication in 1905. While he described the second specimen discovered in 1902 as Tyrannosaurus rex , he assigned the other skeleton, discovered in 1900, to a different new species and genus, which he named Dynamosaurus imperiosus . In 1906, Osborn realized that both skeletons belonged to the same species and chose Tyrannosaurus as a valid name. The Dynamosaurus bones are now in the collection of the Natural History Museum in London .

Brown discovered a total of five partial skeletons of Tyrannosaurus . In 1941, Brown's discovery from 1902, the holotype specimen at the Carnegie Museum of Natural History in Pittsburgh ( Pennsylvania sold). Brown's fourth and largest find, also from the Hell Creek Formation, can be viewed in the American Museum of Natural History in New York .

More recent finds

Although numerous skeletons have been discovered, only a single footprint is documented, located at the Philmont Scout Ranch in northeastern New Mexico . This print was discovered in 1983 and identified and documented in 1994.

In 1990, “ Sue ”, the most complete and best preserved skeleton of a Tyrannosaurus rex to date, was found.

A 2012 find in Montana contained the most completely preserved skull to date. The remains, baptized “ Tristan Otto ”, have been examined in the Museum für Naturkunde in Berlin since July 2015 and have been exhibited there since December 2015.

In 2019, a study of a skeleton discovered in 1991 in Saskatchewan, Canada, was published. It was embedded in such massive sandstone that it took more than 10 years to excavate. RSM P2523.8 ("Scotty") got its name from the celebration at the skeleton find, at which "Scotty" was toasted with a bottle of scotch . "Scotty" is 65% preserved and exceeds the previous size record holder "Sue". With a length of at least 13 meters and an estimated weight of over 8.8 tons, "Scotty" is the largest and heaviest tyrannosaurus discovered worldwide.


Postage stamp of the German Federal Post Office (2008)
Foot of a Tyrannosaurus , Field Museum, Chicago

Tyrannosaurs in general and the species Tyrannosaurus rex in particular are among the world's most popular dinosaurs. For many people, it may be true that Tyrannosaurus rex is the only dinosaur whose full scientific name they know. In modern pop culture, Tyrannosaurus rex is still the epitome of the "deadly eating machine" and a pop culture icon, the epitome of strength and superiority. So far, the more recent theories and findings about possible life as a scavenger have not been able to change much.

Has left a lasting impression the Image of Tyrannosaurus rex also by the technical tricks revolutionary representation in the film Jurassic Park (1993). Here he was characterized as an enormously fast, overpowering creature from which humans could only flee. The film's sound designers also created a well-known, signature roar for the animal.


  • John R. Horner , Don Lessem: The Complete T. Rex. Simon & Schuster, New York NY a. a. 1993, ISBN 0-671-74185-3 .
  • William L. Abler: The Teeth of the Tyrannosaurs. In: Gregory S. Paul (Ed.): The Scientific American book of Dinosaurs. St. Martin's Griffin, New York NY 2000, ISBN 0-312-26226-4 , pp. 276-278.
  • Gregory M. Erickson: Breathing Life into Tyrannosaurus Rex. In: Gregory S. Paul (Ed.): The Scientific American book of Dinosaurs. St. Martin's Griffin, New York NY 2000, ISBN 0-312-26226-4 , pp. 267-275.
  • Rebecca R. Hanna: Dinosaurs Got Hurt Too. In: Gregory S. Paul (Ed.): The Scientific American book of Dinosaurs. St. Martin's Griffin, New York NY 2000, ISBN 0-312-26226-4 , pp. 119-126.
  • David B. Weishampel , Peter Dodson , Halszka Osmólska (eds.): The Dinosauria . 2nd edition. University of California Press, Berkeley CA et al. a. 2004, ISBN 0-520-24209-2 .

Web links

Commons : Tyrannosaurus  - Collection of images, videos and audio files

Individual evidence

  1. ^ Gregory S. Paul : The Princeton Field Guide To Dinosaurs. Princeton University Press, Princeton NJ u. a. 2010, ISBN 978-0-691-13720-9 , p. 69, online .
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