Tyrannosaurus rex

[Life]

Tyrannosaurus rex


© @ DeviantArt user DerpyDuckArt

Temporal range: Late (Upper) Cretaceous (Maastrichtian; ~68-66Ma)

Scientific classification:

Life
Domain: Eukaryota
(unranked): Unikonta
(unranked): Opisthokonta
(unranked): Holozoa
(unranked): Filozoa
Kingdom: Animalia
Subkingdom: Eumetazoa
(unranked): Bilateria
Clade: Nephrozoa
Superphylum: Deuterostomia
Phylum: Chordata
Clade: Olfactores
Clade: Craniata
Subphylum: Vertebrata
Infraphylum: Gnathostomata
Clade: Eugnathostomata
Clade: Teleostomi
Superclass: Tetrapoda
Clade: Reptiliomorpha
Clade: Amniota
Class: Reptilia
Clade: Eureptilia
Clade: Romeriida
Clade: Diapsida
Clade: Neodiapsida
Clade: Archelosauria
Clade: Archosauromorpha
Clade: Archosauriformes
Clade: Crurotarsi
Clade: Archosauria
Clade: Avemetatarsalia
Clade: Ornithodira
Clade: Dinosauromorpha
Clade: Dinosauriformes
Clade: Dinosauria
Order: Saurischia
Clade: Eusaurischia
Suborder: Theropoda
Clade: Neotheropoda
Clade: Averostra
Clade: Tetanurae
Clade: Orionides
Clade: Avetheropoda
Clade: Coelurosauria
Clade: Tyrannoraptora
Superfamily: †Tyrannosauroidea
Family: †Tyrannosauridae
Subfamily: †Tyrannosaurinae
Tribe: †Tyrannosaurini
Genus: †Tyrannosaurus
Species: †T. rex

One of the largest dinosaurs that ever lived, Tyrannosaurus rex was a fierce carnivore. Scientists believe this powerful predator could eat up to 500 pounds (230 kilograms) of meat in one bite.

Fast Facts

Type: Prehistoric

Diet: Carnivore

Size: 40 ft (12 m) long; 10 to 11,5 ft (3 to 3,5 m) tall, 5 to 8 tonnes

Protection status: Extinct

Description:
The Tyrannosaurus rex was a tyrannosaurid carnivore from the Late Cretaceous of North America. The earliest documented discovery of a Tyrannosaurus fossil dates back to 1874, although it did not receive a scientific name until the description by H. F. Osborn in 1905.[1] Its most famous and complete skeleton belongs to the (often presumed to be female) specimens FMNH PR2081 (nicknamed „Sue“). Her length is estimated at 12.29 m[2] and her body mass at ~8 metric tons[4]. Earlier estimates of 9.5 to 18 t have been found to be faulty (see the „correction“ in the footnote).[2] The specimen was for a long time considered to be the largest, until the specimen RSM P2523.8 („Scotty“) usurped her throne in 2019 with an estimated mass somewhat higher, however it may not be larger.[4]

Most adult specimens likely weighed between 6 and 7 tonnes.[2]

"Sue“'s skull has a length of 138 to 140.7 cm from the tip to the back of the quadratojugal, depending on the exact measurement method.[5]
Barring the largest terrestrial crocodiles, Tyrannosaurus likely possessed the strongest bite of any terrestrial animal with estimates ranging from 35 to 57 kN. In Bates and Falkingham's 2012 study of Tyrannosaurus' bite force, MDA models of various other species had been scaled to the same mass of the adult Tyrannosaurus. The results showed midline bite force of an adult Tyrannosaurus still exceeding those of all other scaled-up MDA models, including a scaled-up American alligator (Figure 2d).[6]

Currently, studies and information regarding Tyrannosaurus’ speed suggest that, whereas it was a relatively fast and cursorial animal for its size, its absolute speed was limited by its sheer mass. Biomechanical studies suggest top speeds around 8 meters per second, more or less.[7][8][9] It has been noted several times over the years how Tyrannosaurus contrasts with modern elephants (the only extant terrestrial animals that rival it in body mass), particularly in being far more adapted for fast locomotion than they are.[10][11][12][13][14]

Pop cultural significance:
Tyrannosaurus is the most iconic dinosaur known to man, being widely studied and having rich representation in movies, literature and newspaper articles.
It has been introduced to a broader audience (along with dinosaurs in general) through the 1925 movie The Lost World, although its most iconic appearance lies in the Jurassic Park franchise. It is very common for fictional carnivorous dinosaurs (especially comedic portrayals) to reference the name of Tyrannosaurus rex (one example would be the "Squidasaurus rex" from SpongeBob).
Unsurprisingly, the T. rex is also a mainstay in many dinosaur documentaries, including Walking With Dinosaurs, When Dinosaurs Roamed North America and Dinosaur Revolution.
Even among non-scientists, the name Tyrannosaurus rex is probably the most widely-known binomial name, only rivaled by Homo sapiens.[15]

Did you know? Tyrannosaurus means "tyrant lizard."

Size relative to a bus:



Tyrannosaurus rex was one of the largest meat-eating dinosaurs that ever lived. Everything about this ferocious predator, from its thick, heavy skull to its 5-foot-long (1.5-meter-long) jaw, was designed for maximum bone-crushing action.

Fossil evidence shows that Tyrannosaurus was about 40 feet (12 meters) long and about 10 to 11,5 ft (3 to 3,5 m) tall. Its strong thighs and long, powerful tail helped it move quickly, and its massive 4,6-foot-long (1.4-meter-long) skull could bore into prey.

T. rex's serrated, ziphodont teeth were most likely used to pierce and grip flesh, which it then ripped away with its brawny neck muscles. Its two-fingered forearms could probably seize prey, but they were too short to reach its mouth.

Scientists believe this powerful predator could eat up to 500 pounds (230 kilograms) of meat in one bite. Fossils of T. rex prey, including Triceratops and Edmontosaurus, suggest T. rex crushed and broke bones as it ate, and broken bones have been found in its dung.

Tyrannosaurus rex lived in forested river valleys in North America during the late Cretaceous period. It became extinct about 66 million years ago in the Cretaceous-Tertiary mass extinction.

Source: animals.nationalgeographic.com/animals/prehistoric/tyrannosaurus-rex.html

Additional Resources:

Unearthing T.rex

100 years of Tyrannosaurus rex (Tetrapod Zoology)

Footnotes:
[1] Breithaupt, B. H.; Southwell, E. H.; Matthews, N. A. (2005). In Celebration of 100 years of Tyrannosaurus rex: Manospondylus gigas, Ornithomimus grandis, and Dynamosaurus imperiosus, the Earliest Discoveries of Tyrannosaurus rex in the West. (link) Abstracts with Programs; 2005 Salt Lake City Annual Meeting. Geological Society of America. 37 (7): 406.
[2] Hutchinson, J. R.; Bates, K. T.; Molnar, J.; Allen, V.; Makovicky, P. J. (2011). A Computational Analysis of Limb and Body Dimensions in Tyrannosaurus rex with Implications for Locomotion, Ontogeny, and Growth. PLoS ONE. 6 (10): e26037. doi:10.1371/journal.pone.0026037 (link). PMC 3192160. PMID 22022500.
[3] Hartman, Scott (2013). Mass estimates: North vs South redux. (link)
[4] Persons, W. Scott; Currie, Philip J.; Erickson, Gregory M. (2019). An Older and Exceptionally Large Adult Specimen of Tyrannosaurus rex. The Anatomical Record. doi:10.1002/ar.24118 (link). ISSN 1932-8486.
[5] Brochu, Christopher (2003) Osteology of Tyrannosaurus rex: Insights from a Nearly Complete Skeleton and High-Resolution Computed Tomographic Analysis of the Skull 22:1-138 doi:10.1080/02724634.2003.10010947 (link)
[6] Bates, K. T.; Falkingham, P. L. (2012). Estimating maximum bite performance in Tyrannosaurus rex using multi-body dynamics. Biological Letters. 8 (4): 660–664. doi:10.1098/rsbl.2012.0056 (link).
[7] Sellers, W.I.; Manning, P.L. (2007). Estimating dinosaur maximum running speeds using evolutionary robotics. 274 Proc. R. Soc. B. doi: 10.1098/rspb.2007.0846.
[8] Sellers, W.I.; Pond, S.B.; Brassey, B.A.; Manning, P.L.; Bates, K. T. (2017). Investigating the running abilities of Tyrannosaurus rex using stress-constrained multibody dynamic analysis[/url]. PeerJ 5:e3420 doi.org/10.7717/peerj.3420
[9] Hutchinson, J.R.; Gatesy, S.M. (2006). Dinosaur Locomotion: Beyond the bones. Nature.
[10] Bakker, R.T. (1986). The Dinosaur Heresies. Citadel Press.
[11] Paul, G.S. (1988). Predatory Dinosaurs of the World: A Complete Illustrated Guide. Simon & Schuster.
[12] Paul, G.S. (1998). Limb design, function and running performance in ostrich-mimics and tyrannosaurs. Gaia, 257-270.
[13] Paul, G.S. (2008). The Extreme Lifestyles and Habits of the Gigantic Tyrannosaurid Superpredators of the Late Cretaceous of North America and Asia in Tyrannosaurus rex, the Tyrant King. Indiana University Press.
[14] Paul, G.S. (2016). The Princeton Field Guide to Dinosaurs (2nd Edition). Princeton University Press. p. 31.
[15] Busby III, Arthur; et al. (1997). A Guide to Rocks and Fossils. p. 103.[/a]

[Life]

Cranial mechanics and feeding in Tyrannosaurus rex

Abstract

It has been suggested that the large theropod dinosaur Tyrannosaurus rex was capable of producing extremely powerful bite forces and resisting multi–directional loading generated during feeding. Contrary to this suggestion is the observation that the cranium is composed of often loosely articulated facial bones, although these bones may have performed a shock–absorption role. The structural analysis technique finite element analysis (FEA) is employed here to investigate the functional morphology and cranial mechanics of the T. rex skull. In particular, I test whether the skull is optimized for the resistance of large bi–directional feeding loads, whether mobile joints are adapted for the localized resistance of feeding–induced stress and strain, and whether mobile joints act to weaken or strengthen the skull overall. The results demonstrate that the cranium is equally adapted to resist biting or tearing forces and therefore the‘puncture–pul’ feeding hypothesis is well supported. Finite–element–generated stress–strain patterns are consistent with T. rex cranial morphology: the maxilla–jugal suture provides a tensile shock–absorbing function that reduces localized tension yet ‘weakens’ the skull overall. Furthermore, peak compressive and shear stresses localize in the nasals rather than the fronto–parietal region as seen in Allosaurus, offering a reason why robusticity is commonplace in tyrannosaurid nasals.

Source: rspb.royalsocietypublishing.org/content/271/1547/1451.abstract

For full details: click here (PDF download warning)

[Life]

SUE

Scientific name: Tyrannosaurus rex (From the Greek and Latin for "tyrant lizard king")

Time: Late Cretaceous Period 67 million years ago

Range: Alberta (Canada), and Montana, Wyoming, Colorado, Utah, and North and South Dakota (U.S.A.)

Environment: Warm, lush, and seasonally damp

Discovered: August 12, 1990, on the Cheyenne River Sioux Indian Reservation near Faith, South Dakota, by fossil hunter Sue Hendrickson

Length: 40.5 feet (12.3 meters)

Height at hips: 13 feet (4.0 meters)

Estimated live weight: more than 7 tons (6.4 metric tons)

Weight of skeleton: 3,922 pounds (1.78 metric tons)

Weight of skull: 600 pounds (272 kg)

Size of brain cavity: pint-sized

Number of teeth: 58

Length of teeth: 7.5 to 12 inches (19.05 to 30.5 centimeters)

Bite Force: at least 13,400 newtons (3,012 pounds)

Diet: Meat

Gender: Unknown

Age: 28 years at death

Length of skull: 5 feet (1.5 meters)

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SUE's Senses

Like all T. rex, SUE's diet was made up of meat—mostly plant-eating dinosaurs. A creature her size probably had to both hunt and scavenge to get enough to eat. Her skeleton tells us that her body was built for her lifestyle.

Eyesight: On SUE's skull, her eye sockets faced forward, as do those of most other predators and scavengers, including humans. This means SUE had good depth perception and could tell how far away her next meal was.

Hearing: The internal structure of SUE's ear was much like yours. In fact, T. rex had the best hearing of all theropod dinosaurs and could probably easily hear potential prey approaching.

Sense of smell: Based on the length of SUE's snout and the size of the odor-detecting region in her brain, scientists think that SUE had a keen sense of smell. She would've had no problem sniffing out carrion or potential prey, but likely hunted by sight more than scent.

Bite Force: SUE's serrated teeth were perfect for biting through flesh and bone. Their backwardly curved shape also prevented struggling meals from escaping. Estimates of a T. rex's bite force places it higher than the largest living alligator or crocodile.

Speed & Agility: As a rule in nature, extremely large animals like elephants are not as fast as mid-sized animals like horses or antelope. That's why scientists think that SUE couldn't run fast. Her top speed was probably only 15 mph—still faster than most of her prey.

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Official link: www.fieldmuseum.org/sue/#index

[Life]

T. Rex Quicker Than Professional Athlete, Say Scientists



ScienceDaily (Aug. 23, 2007) — T. rex may have struggled to chase down speeding vehicles as the movie Jurassic Park would have us believe but the world's most fearsome carnivore was certainly no slouch, new research out suggests.

The University of Manchester study used a powerful supercomputer to calculate the running speeds of five meat-eating dinosaurs that varied in size from a 3kg Compsognathus to a six-tonne Tyrannosaurus.

The study -- believed to be the most accurate ever produced -- puts the T. rex at speeds of up to 18mph, fractionally quicker than a sportsman such as a professional soccer player.

The bipedal Compsognathus, by comparison, could reach speeds of almost 40mph -- that's 5mph faster than the computer's estimate for the fastest living animal on two legs, the ostrich.

The team -- headed by biomechanics expert Bill Sellers and palaeontologist Phil Manning -- say the accuracy of their results is due to the computer's ability to use data relating directly to each dinosaur.

"Previous research has relied on data from extant bipedal models to provide clues as to how fast dinosaurs could run," said Dr Sellers, who is based in Manchester's Faculty of Life Sciences.

"Such calculations can accurately predict the top speed of a six-tonne chicken but dinosaurs are not built like chickens and nor do they run like them.

"Our research involved feeding information about the skeletal and muscular structure of the dinosaurs directly into the supercomputer so it could work out how the animals were best able to move."

Despite its powerful memory and 256 processors the computer still took up to a week to learn the biomechanics of each animal -- starting with the first clumsy steps and developing into a top running speed based on the optimum gait and posture.

The first data to be fed into the computer were those of a 70kg human with the muscle and bone structure of a professional sportsman. The computer accurately predicted a top running speed of just under the 8 metres per second of T. rex.

Musculoskeletal details of a 30kg South American emu and a 65kg ostrich were fed into the program next and top running speeds of 13m/s (about 30mph) and 15m/s (35mph) were calculated respectively.

The process was then repeated using the musculoskeletal data of five bipedal meat-eating dinosaurs -- a 3kg Compsognathus, a 20kg Velociraptor, a 430kg Dilophosaurus, a 1.4 tonne Allosaurus and the 6 tonne Tyrannosaurus.

"The figures we have produced are the best estimate to date as to how fast these prehistoric animals could run," said collaborator Dr Manning, a lecturer in palaeontology in the School of Earth, Atmospheric and Environmental Sciences.

"Since the movie Jurassic Park, scientists have questioned the speed of these dinosaurs and some have wondered whether Tyrannosaurus could have run at all.

"Our research, which used the minimum leg-muscle mass T. rex required for movement, suggests that while not incredibly fast, this carnivore was certainly capable of running and would have little difficulty in chasing down footballer David Beckham for instance."

Source: www.sciencedaily.com/releases/2007/08/070822081928.htm

[Life]

T.Rex Fossils Yield Soft Tissue

Material may contain preserved biomolecules



In a discovery that invokes comparisons to Jurassic Park, North Carolina State University paleontologist Mary Schweitzer and her colleagues have extracted soft tissue from the fossilized leg bone of a 70-million-year-old Tyrannosaurus rex specimen. The soft tissue includes intact, still-flexible blood vessels and fibrous material consistent with collagen. Also, electron microscopy reveals round-to-oval bodies virtually identical to the cell nuclei found in the corresponding tissues of ostriches, which, along wtih other birds, are believed to be modern-day descendants of dinosaurs.

Whether the tissue will yield DNA or any other biomolecules remains to be answered.

Schweitzer and her team published the finding in the March 25 issue of the journal Science.

The presence of this novel tissue is not the only surprise from this discovery, says Enriqueta Barrera, a program director in the National Science Foundation's earth sciences division, which partly funded the study. The tissue was once elastic and stretchy, and had the capacity to be dehydrated and rehydrated many times without losing this characteristic. “Although the preservation of soft tissue such as this is not unique in the geologic record, this occurrence goes well beyond what has been observed in the past for dinosaurs, and reinforces the evolutionary link of dinosaurs to birds,” said Barrera.

Source: www.nsf.gov/news/news_summ.jsp?org=NSF&cntn_id=103152&preview=false

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Analyses of Soft Tissue from Tyrannosaurus rex Suggest the Presence of Protein

We performed multiple analyses of Tyrannosaurus rex (specimen MOR 1125) fibrous cortical and medullary tissues remaining after demineralization. The results indicate that collagen I, the main organic component of bone, has been preserved in low concentrations in these tissues. The findings were independently confirmed by mass spectrometry. We propose a possible chemical pathway that may contribute to this preservation. The presence of endogenous protein in dinosaur bone may validate hypotheses about evolutionary relationships, rates, and patterns of molecular change and degradation, as well as the chemical stability of molecules over time.

Source: www.sciencemag.org/cgi/content/abstract/sci;316/5822/277

For full details: click here (PDF download warning)

[Life]

The terrible teens of T. rex

In a new scientific paper, researchers from Northern Illinois University and the Burpee Museum of Natural History in Rockford, Ill., report that adolescent tyrannosaurs got into some serious scraps with their peers. The evidence can be found on Jane, the museum's prized juvenile Tyrannosaurus rex. Jane's fossils show that she sustained a serious bite that punctured through the bone of the dinosaur's upper maxilla, the researchers report. In this photo of the upper left maxilla of Jane, three of four elliptical-shaped puncture wounds are evident. The researchers determined that another juvenile tyrannosaur was responsible for the injury. Credit: Joe Peterson, NIU

We all know adolescents get testy from time to time. Thank goodness we don't have young tyrannosaurs running around the neighborhood.

In a new scientific paper, researchers from Northern Illinois University and the Burpee Museum of Natural History in Rockford report that adolescent tyrannosaurs got into some serious scraps with their peers.

The evidence can be found on Jane, the museum's prized juvenile Tyrannosaurus rex, discovered in 2001 in Montana.

Jane's fossils show that she sustained a serious bite that punctured through the bone of the dinosaur's left upper jaw and snout in four places, the researchers report. The injury wasn't life threatening and eventually healed over, according to the scientists.

The bite did leave scars, however.

"Jane has what we call a boxer's nose," says Joe Peterson, an NIU Ph.D. candidate in geology and lead author of the study published in the November issue of the journal, Palaios.

"Her snout bends slightly to the left. It was probably broken and healed back crooked."

The researchers determined that another juvenile tyrannosaur was responsible for the injury.

"Only a few animals could have inflicted the wound," Peterson says, noting that the bite marks were oblong-shaped. A crocodile or an adult T. rex would have left different types of bite marks.

"When we looked at the jaw and teeth of Jane, we realized her bite would have produced a very close match to the injuries on her own face," Peterson says. "That leads us to believe she was attacked by a member of the same species that was about the same age. Because the wound had healed, we think this happened when Jane was possibly a few years younger."

Peterson and Mike Henderson, curator of earth sciences at the Burpee Museum and also a Ph.D. candidate in geology at NIU, were members of the museum group that unearthed the pristine dinosaur skeleton. NIU Presidential Research Professor Reed Scherer, also among the new study's authors, worked as an adviser on the find.

NIU's Reed Scherer (left to right), Mike Henderson and Joe Peterson examine Jane's upper jawbone at the Burpee Museum. Credit: NIU photo by Scott Walstrom

"What's unique about this work is we learn something very, very specific about juvenile dinosaur behavior," Scherer says. "This was an animal about the same size that attacked Jane. Whether it was a sibling or from a rival group, we don't know, but it's fun to speculate."

The sex of Jane, who was named after a museum donor, is unknown. The dinosaur was young when it died, but the Burpee Museum's display leaves no doubt that it was still a creature to be reckoned with. Twenty-two feet long and 7 1/2 feet high at the hip, the young dinosaur tipped the scales at about 1,500 pounds. And it was built to kill, with 71 serrated teeth.

Still, Jane was vastly smaller than an adult T. rex. After much study and consultation with leading U.S. dinosaur experts, Henderson, who led the Montana expeditions, announced in 2006 that Jane was a late juvenile T. rex, about 11 or 12 years old.

"The study of the bite marks on Jane's face demonstrates that even at a young age this dinosaur was engaging in some pretty serious combat," Peterson says. He likened the animal to an adolescent that hadn't quite reached what would have been a huge growth spurt.

The puncture wounds were first noticed several years after the dinosaur was discovered.

"When Jane's skull was found, the bones were disarticulated, or in pieces," Peterson says. "I was examining the casts of the skull bones. I saw that when the left maxilla (upper jawbone) was pieced together, it had more holes in it than the right side. And there was a pattern to the gaps in the side of the face.

"The surface of the face and edges around the puncture marks were smooth, indicating that there hadn't been a fresh break there and the wounds must have healed over while the animal was alive," he adds.

Dr. Christopher Vittore, a Burpee Museum board member and radiologist at Rockford Memorial Hospital, who also contributed to the study in Palaios, took CT scans of the fossils and confirmed Peterson's hypothesis.

"CT scans demonstrated that the holes are most consistent with traumatic puncture injuries that had significant time for healing," Vittore says.

"Complete bone healing requires time for bone remodeling, and CT images show the internal structure of the bone adjacent to the puncture lesions," Vittore adds. "The internal character of the bone showed the injuries occurred significantly earlier in the animal's life, and there was time for healing. It also confirmed that there were no other abnormalities in the bone adjacent to the lesions."

Lead author Joe Peterson stands in front of the display of Jane at the Burpee Museum in Rockford, Ill. Credit: Northern Illinois University photo by Scott Walstrom

Because the dinosaur had not reached maturity, the researchers concluded that the combat was not likely over sexual conflict or competition but might have been a learning behavior for young dinosaurs prompted by a show of dominance or territorial dispute.

Peterson says other adolescent animals, particularly juvenile crocodiles, exhibit such fighting behavior.

"It's common to find similar puncture marks on young crocodiles," he says. "We can look at the behavior of these modern living ancestors of dinosaurs and get a good idea of what was going on here."

A recent study suggested that, in some dinosaurs, apparent bite marks are actually holes in the skull caused by a parasite. Researchers speculated that such a parasitic infection might have led to the demise of Sue, the famous T. rex at the Field Museum in Chicago.

NIU researchers don't believe a parasite caused Jane's injuries.

"The parasite that has been described causes lesions on the lower jaw," Peterson says. "With Jane, the lesions are on the actual face and are not the same type of structures we see on Sue."

Source: www.physorg.com/news176386597.html

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Additional Resources:

Bite Marks Show T. Rex Teens Fought Viciously

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[Life]

Source: www.karencarr.com/tmpl1.php?CID=311

[Life]

T.Rex - Warrior Or Wimp?

Tyrannosaurus rex - it's the scariest, meanest, most bewitching dinosaur of them all. Children are captivated by the sheer savagery of the teeth. Experts marvelled at the force of its bite - ten times more powerful than anything we know today. Moviemakers made millions out of the terror it inspired. But could our picture of this monster be completely wrong?

Was T. rex in fact a slow lumbering creature, with hideously bad breath, that couldn't get anywhere close to catching a Triceratops. Was it really a scavenger that lived off the scraps left by others? Was T. rex, in fact, a wimp?

Featuring fabulous graphics and interviews with T. rex experts from around the world, Horizon looks at the new science that is challenging the legend of the dinosaur we love to hate.

Source: www.bbc.co.uk/science/horizon/2004/trex.shtml

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[Life]

T. Rex Bite Strongest Ever on Land—Ten Times Greater Than Gator's

Dinosaur still no match for prehistoric "megatooth" sharks.

images.nationalgeographic.com/wpf/media-live/photos/000/493/cache/tyrannosaurus-rex-bite-power_49360_600x450.jpg

The recontructed skull musculature of a South Dakota T. rex (file picture).
Photograph by Ira Block; model by Brian Cooley

Once the largest known carnivore on land, Tyrannosaurus rex also had the most powerful bite of any terrestrial animal of any time period, a new study suggests.

(Related video: "T. Rex's Bone-Shattering Bite Filmed.")

Much conventional wisdom about the world's most famous dinosaur species has been called into question in recent years—for instance, whether the 40-foot-long (12-meter-long) T. rex species could run or only plod along.

Likewise, some have contended that the supposedly mighty predator actually had a modest bite, limiting T. rex to scavenging.

To see how forcefully T. rex could bite, biomechanicists involved in the new study used laser scanners to digitize juvenile and adult T. rex skulls. The team then used computer models to reconstruct the dinosaur's jaw muscles and analyze bite performance.

The models suggest that an adult T. rex was capable of a maximum bite force of 35,000 to 57,000 newtons at its back teeth. That's more than four times higher than past estimates and ten times as forceful as the bite of a modern alligator.

T. rex, which went extinct about 65 million years ago, "probably lives up to its reputation as a ferocious biter," concluded study leader Karl Bates, a computational anatomist at the University of Liverpool in the United Kingdom.

(Also see "New 'Destroyer' Dinosaur Found—Was T. Rex Relative.")

T. Rex No Match for Megatooth?

Although T. rex may have possessed the most powerful bite of any land animal, it apparently paled in comparison to that of prehistoric megalodon—literally "megatooth"—sharks, which may have grown to lengths of more than 50 feet (16 meters) and weighed up to 30 times more than the largest great white.

Past megalodon research suggests these giant marine predators, which first appeared around 16 million years ago, could chomp with more than three times the force of T. rex, based on the new figures.

The bite force of a megalodon—"just because it was so much larger-bodied—would have been bigger," Bates said.

So T. rex could have bitten with ten times the force of an alligator. But would it have?

Answering that question would require an estimate of how much stress T. rex's skull could take, Bates said—to help pinpoint just how forcefully the predator could have bitten down with without hurting itself.

Source: news.nationalgeographic.com/news/2012/120228-t-rex-bite-bates-science-biology-letters-dinosaurs/

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Estimating maximum bite performance in Tyrannosaurus rex using multi-body dynamics

Abstract

Bite mechanics and feeding behaviour in Tyrannosaurus rex are controversial. Some contend that a modest bite mechanically limited T. rex to scavenging, while others argue that high bite forces facilitated a predatory mode of life. We use dynamic musculoskeletal models to simulate maximal biting in T. rex. Models predict that adult T. rex generated sustained bite forces of 35 000–57 000 N at a single posterior tooth, by far the highest bite forces estimated for any terrestrial animal. Scaling analyses suggest that adult T. rex had a strong bite for its body size, and that bite performance increased allometrically during ontogeny. Positive allometry in bite performance during growth may have facilitated an ontogenetic change in feeding behaviour in T. rex, associated with an expansion of prey range in adults to include the largest contemporaneous animals.

Source: rsbl.royalsocietypublishing.org/content/early/2012/02/25/rsbl.2012.0056.short

[Grey]

The preserved skull of the largest reasonnably complete Tyrannosaurus individual, Sue.



Upper jaw of the Tyrannosaurus holotype.



T. rex individual Stan.

[Grey]

An excellent lecture talk of Thomas Holtz about Tyrannosaurus.

[theropod]

New skeletals of sue and stan by Scott Hartman:
scotthartman.deviantart.com/art/Stan-n-Sue-comparison-360918612

The legs seem shorter and the skull shape is different, more like the mount. Shartman states he based it off the skeletal scan (Hutchinson et al. 2011)

Measurements at a femur lenght of 131px:
1135px long (not along the curves)
332px tall (legs not fully stretched out)
141px long skull (Pmx-Qj)

[creature386]

Very informative book:
books.google.com/books?id=5WH9RnfKco4C&lpg=PP1&hl=de&pg=PP1#v=onepage&q&f=false

[theropod]

The large theropod dinosaur Tyrannosaurus rex underwent remarkable changes during its growth from ,10 kg hatchlings
to .6000 kg adults in ,20 years. These changes raise fascinating questions about the morphological transformations
involved, peak growth rates, and scaling of limb muscle sizes as well as the bodyÂ’s centre of mass that could have
influenced ontogenetic changes of locomotion in T. rex. Here we address these questions using three-dimensionally
scanned computer models of four large, well-preserved fossil specimens as well as a putative juvenile individual.
Furthermore we quantify the variations of estimated body mass, centre of mass and segment dimensions, to characterize
inaccuracies in our reconstructions. These inaccuracies include not only subjectivity but also incomplete preservation and
inconsistent articulations of museum skeletons. Although those problems cause ambiguity, we conclude that adult T. rex
had body masses around 6000–8000 kg, with the largest known specimen (‘‘Sue’’) perhaps ,9500 kg(*). Our results show
that during T. rex ontogeny, the torso became longer and heavier whereas the limbs became proportionately shorter and
lighter. Our estimates of peak growth rates are about twice as rapid as previous ones but generally support previous
methods, despite biases caused by the usage of scale models and equations that underestimate body masses. We
tentatively infer that the hindlimb extensor muscles masses, including the large tail muscle M. caudofemoralis longus, may
have decreased in their relative size as the centre of mass shifted craniodorsally during T. rex ontogeny. Such ontogenetic
changes would have worsened any relative or absolute decline of maximal locomotor performance. Regardless, T. rex
probably had hip and thigh muscles relatively larger than any extant animal’s. Overall, the limb ‘‘antigravity’’ muscles may
have been as large as or even larger than those of ratite birds, which themselves have the most muscular limbs of any
living animal.

A Computational Analysis of Limb and Body Dimensions
in Tyrannosaurus rex with Implications for Locomotion,
Ontogeny, and Growth
John R. Hutchinson1*, Karl T. Bates2, Julia Molnar1, Vivian Allen1, Peter J. Makovicky3


* among the highest values ever published, so definitely on the upper end.

Abstract.—Tyrannosaurus rex and other tyrannosaurid theropods exerted high bite forces, and large
muscle attachments suggest that the tyrannosaurid neck was a concomitantly powerful component
of the feeding apparatus. We examine accelerative and work-generating capacity (WGC) of neck
muscles in adult Tyrannosaurus rex, using a 3-D vector-based method that incorporates aspects of
muscle force generation, reconstruction of muscle morphology and moment arms, and rotational
inertias of the head and neck. Under conservative assumptions, radial accelerations of the head by
large superficial muscles (M. transversospinalis capitis, M. complexus, and M. longissimus capitis
superficialis) enabled rapid gaze shifts and imparted high tangential velocities to food sufficient
for inertial feeding. High WGC by these and deeper muscles under eccentric contraction indicate
high efficacy for tearing flesh, especially with the head and neck in an extended posture. Sensitivity
analyses suggest that assigned density of the antorbital region has substantial effects on calculated
rotational inertia, and hence on the accuracy of results. However, even with high latitude for es-
timation errors, the results indicate that adult T. rex could strike rapidly at prey and engage in
complexly modulated inertial feeding, as seen in extant archosaurs.

Craniocervical feeding dynamics of Tyrannosaurus rex
Eric Snively and Anthony P. Russell

[creature386]

Detailed paper about the osteology of the specimen "Sue":
www.tandfonline.com/doi/abs/10.1080/02724634.2003.10010947