stan_trex_skull_Here is one of the most famous T.rex skulls of all time. This specimen nicknamed "Stan", in honor of amateur paleontologist Stan Sacrison, was found in the Hell Creek Formation near Buffalo, South Dakota, in the spring of 1987. After 30,000 hours of digging and preparing, a 65% complete skeleton emerged. This tyrannosaur was found to have many bone pathologies, including broken and healed ribs, a broken (and healed) neck and a spectacular hole in the back of its head, about the size of a front lower Tyrannosaurus tooth

Tyrannosaurus rexBHI 3033 (1/6-scale replica)

"Stan"

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Stanhttp://nl.wikipedia.org/wiki/Stan_(dinosauri%C3%ABr)

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trex_harleyTyrannosaurus Rex "Harley" fossil skull This cast replica comes from the Cretaceous Hell Creek formation, Jordan, Montana. The original is in Los Angeles County Museum of Natural History specimen. 

trex_skeleton_cast_ Sue

Sue

Sue Tyrannosaurus rex — American Museum of Natural History

…de grootste T. rex mogelijk meer dan 9000 kilo woog?

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trex_brain_ This is a cast of the inside of a T-rex brain cavity.  Measures 7 inches. 

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Tyrannosaur, any of a group of predatory dinosaurs that lived from the late Jurassic Period (about 150 million years ago) to the latest Cretaceous Period (about 65 million years ago), at which time they reached their greatest dominance. 

Most tyrannosaurs were large predators, with very large, high skulls approaching or well exceeding a full metre (more than three feet) in length.The best-known and largest member of the group is Tyrannosaurus rex, or T. rex. , walked on powerfully developed hind limbs. If the animal had stood upright, it would have been more than 6.5 metres (21 feet) tall, but the usual posture was horizontal, with the body carried parallel to the ground and the tail held off the ground as a counterbalance.In this position a large adult, weighing 4,000 to 7,000 kg (about 9,000 to 15,000 pounds), could measure 14 metres long.

The longest known tyrannosaur skull is 1.3 metres (more than 4 feet) long. The skull bones of large tyrannosaurs are often several centimetres thick and are strongly braced to each other, which suggests a resistance to the forces of biting, both inflicted upon and received from other tyrannosaurs. Engineering models, in fact, show that the bite force of T. rex would easily have been capable of ripping through a

car roofThe huge mouth contained some 60 teeth, which could protrude as far as 15 cm (6 inches). The crowns of the teeth were shed and regrown frequently (every 250 days or so, on the basis of microscopic lines visible within the teeth). Serrations of the teeth bear deep pocketlike recesses in which bacteria may have flourished to provide an infectious bite.Tyrannosaur teeth are distinctive. The front teeth are small and U-shaped. The side teeth are large, and in adults they become even larger, fewer in number, and D-shaped in cross section rather than daggerlike as in most theropods, or flesh-eating dinosaurs.In juveniles the teeth are laterally compressed and serrated front and back, like those of other theropods. In mature individuals, however, the teeth fall neatly into three general classes: upper front teeth, upper side teeth, and lower jaw teeth. Gut contents and coprolites (fossilized feces) of tyrannosaurs, as well as remains of other dinosaurs preserved with tyrannosaurid bite marks, show that tyrannosaurs were voracious predators that could easily bite through skulls, pelvises, and limbs of other dinosaurs. Bite marks found on the bones of other tyrannosaurs, especially T. rex, have been interpreted by some scientists as evidence of cannibalism.

Other skeletal features

In contrast to the powerful jaws and legs, the forelimbs of tyrannosaurs were very small (less than the length of the shoulder blade), and in some forms the hands were reduced to only two digits. Although a mechanical reconstruction suggests that the musculature of the arms of T. rex and some other large tyrannosaurs could have lifted about 180 kg (400 pounds), the hands would not have been able to reach the mouth or grasp prey. 

The hind limb bones appear massive but are lightly constructed: the thickness of the bone wall is only about 20 percent of the bones’ diameter—a figure approaching that of many birds.

The age of individual dinosaurs and other vertebrates can be determined by counting the annual growth rings that are laid down in the long bones, in a manner somewhat analogous to counting tree rings.By using a series of bones from early growth stages to adulthood, the life history of an animal species can be reconstructed. Such studies have shown that T. rex effectively reached full size in less than 20 years—approximately the same period as for human beings. Of course, at a length of 6.5 metres and a mass of six tons, T. rex reached a much larger size than humans in 20 years. But its growth rate was not as high as that of some herbivorous dinosaurs such as the hadrosaurs (duck-billed dinosaurs), which reached full size in seven or eight years, or the sauropods (the largest plant-eating dinosaurs), which attained most of their gigantic size in 14 years or so. On the other hand, the growth rate of T. rex was higher than that of the African elephant, which has a similar mass yet a longer time to maturity. Some of the known specimens of T. rex did not quite reach full size; others do not seem to have survived long after achieving it. This may testify to the hard life of Mesozoic dinosaurs.Although it was once thought that male and female tyrannosaurs could be distinguished by the shape of the tail vertebrae near the pelvis, this feature turns out not to be diagnostic. However, one subsequently discovered feature does establish sex. During the reproductive cycles of female birds, a layer of bone (medullary bone) is often deposited on the inner wall of the long bones. This process has been recognized in some fossils of tyrannosaurs (and of a few other dinosaurs), indicating that these specimens are female.

Hell Creek discoveries

Fossils of T. rex are found only in the Hell Creek Formation of Garfield county, Montana, and adjacent areas of the United States, in deposits dating from the Maastrichtian Age, the last time unit of the Cretaceous Period—although slightly earlier relatives such as Tarbosaurus and Raptorex are known from Asia. 

Found in the same deposits as T. rex are fossils of the ceratopsians (giant horned dinosaurs) on which they likely preyed. There is some question about whether tyrannosaurs killed their food or simply scavenged it. However, neither predatory nor scavenging behaviour need be excluded, since T. rex, like many large carnivores today, probably fed opportunistically, scavenging when it could and hunting when it had to. One argument for predation emphasizes T. rex’s vision. The eye sockets tend to be keyhole-shaped and directed forward, which has been taken as evidence for accurate depth perception, because the fields of view of the eyes would overlap. Other evidence supporting predation is the well-protected skull and formidable jaws. Wounds in the bones of its prey indicate that T. rex ate by using a “puncture and tear” stroke, planting its feet and

using the powerful muscles of the neck and legs to anchor itself and pull flesh off bones.

Before 1980 all knowledge of T. rex was based on only four skeletons, none very complete. The Latin name was given to the first specimen by American paleontologist Henry Fairfield Osborn in 1905 and was based on partial specimens collected from the Hell Creek Formation by renowned fossil hunter Barnum Brown. Remains found by Brown are on display at the Carnegie Museum of Natural History in Pittsburgh, Pa., the American Museum of Natural History in New York City, and the Natural History Museum in London.Since 1980 more than two dozen other specimens of T. rex have been discovered in western North America, some very complete; however, some are in private collections and are therefore lost to science and education. Two of the best specimens, consisting of almost complete adult skeletons, were unearthed in 1990. One, the 85-percent-complete “Wankel” T. rex, is on display at the Museum of the Rockies in Bozeman, Mont., and the other, the 90-percent-complete “Sue,” is displayed at the Field Museum in Chicago. Other T. rex specimens are mounted at other natural history museums in North America, such as the Denver Natural History Museum, the University of California Museum of Paleontology in Berkeley, the Natural History Museum of Los Angeles County, and the Royal Tyrrell Museum in Drumheller, Alta., near Dinosaur Provincial Park.

In 2000 five T. rex specimens were discovered in the Hell Creek Formation. Several are now on display at the Museum of the Rockies; one of them, the “B-rex,” preserves soft tissues and also medullary bone that indicates the specimen was female. The soft tissues preserve transparent, flexible, hollow blood vessels that contain small round microstructures highly reminiscent in structure of red blood cells. The preservation of these structures is one of the most amazing features of the entire known fossil record.

Classification

Tyrannosaurs are generally divided into the large but more lightly built and slightly earlier albertosaurines and the still larger, more robust, and later tyrannosaurines.

Most tyrannosaurs are known from the latest Cretaceous, but some basal forms are now known from the Early Cretaceous and even the Late Jurassic, though these earlier forms share few features with their later, well-known relatives. 

Guanlong, an animal about three metres long from the Late Jurassic of Xinjiang province, western China, is the earliest well-known member of the group; it has some primitive and unique features—the most notable being a complex skull crest consisting of a hollow bone running atop the midline of its skull. 

Dilong, an early tyrannosaur 1.5 metres (5 feet) long from the spectacular Liaoning deposits of northeastern China, is preserved with a covering of simple, filamentous “protofeathers” like those seen on many other Early Cretaceous theropod dinosaurs. 

Eotyrannus, from Early Cretaceous deposits on Britain’s Isle of Wight, is also lightly built and relatively small (some 4.5 metres, or 15 feet, long).

These three tyrannosaurs are so primitive that they retain three fingers on their hands.

Several small tyrannosaur fossils from the latest Cretaceous of western North America were once assigned to separate taxa, but most scholars now consider them to be merely young tyrannosaurs. For example, specimens once given the names Nanotyrannus and Stygivenator are now considered to be juvenile tyrannosaurs, and the former Dinotyrannus is now seen as a subadult T. rex. 

T. rex is the only tyrannosaur known from the late Maastrichtian Age (i.e., the latest Cretaceous Period) in North America. 

As is mentioned above, Tarbosaurus is a slightly earlier and very similar form from the latest Cretaceous of Mongolia.

Formally described in 2009, a new genus of earlier and smaller tyrannosaur, Raptorex kriegsteini, is based on a single specimen from the Early Cretaceous of the Inner Mongolia Autonomous Region. It stood roughly 3 metres (10 feet) tall, and its weight was roughly 40 to 70 kg (90 to 150 pounds), about one-hundredth the weight of Tyrannosaurus. Although R. kriegsteini is small for a tyrannosaur, as most of the basal ones are, its body plan—with smaller, D-shaped tooth cross sections and short arms with reduced fingers—closely resembles a reduced version of T. rex.

Tyrannosaurs were long thought to be one of the carnosaurs (“flesh-eating lizards”), related to other large theropods such as the allosaurs. 

These resemblances have proved to be superficial, related to large size alone. 

Today tyrannosaurs are considered to be gigantic members of the coelurosaurs (“hollow-tailed lizards”), a group largely composed of smaller, more-gracile forms. Frequently they have been related to the largely toothless, ostrichlike ornithomimids, mainly because tyrannosaurs and ornithomimids share a peculiar foot with “pinched” foot bones. Tyrannosaurs may turn out to be closely related to the dromaeosaurs, though evidence for this hypothesis is as elusive as any other.

Kevin Padian

LINKS

Year in ReviewBritannica provides coverage of "tyrannosaur" in the following Year in Review articles.

paleontology (in Life Sciences: Year In Review 2010)paleontology (in Life Sciences: Year In Review 2006)

"tyrannosaur." Encyclopædia Britannica. Encyclopædia Britannica Online. Encyclopædia Britannica Inc., 2012. Web. 08 Mar. 2012. .

Encyclopædia Britannica Online, accessed March 8, 2012, http://www.britannica.com/EBchecked/media/9976/Biomechanical-reconstruction-of-a-tyrannosaur-in-motion-showing-skeletal-structure

bipedalism: Tyrannosaurus in motion, showing skeleton. Animation. Encyclopædia Britannica Online. Web. 8 Mar. 2012.

http://www.britannica.com/EBchecked/topic/611883/tyrannosaur

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Tyrannosaurid Dentary from Kazakhstan Jul 1, '12 10:45 AMhttp://ffd2009.multiply.com/journal/item/251

by Neal for group ffd2009 

A Tyrannosaurid dentary was recently found in Kazakhstan. A.O. Averianov, H.-D. Sues, and P.A. Tleuberdina wrote an article titled THE FORGOTTEN DINOSAURS OF ZHETYSU (EASTERN KAZAKHSTAN; LATE CRETACEOUS). It was published in 2012 in Proceedings of the Zoological Institute RAS, Vol. 316, No. 2, pp. 139-147. This quote from the abstract says: 

The Late Cretaceous dinosaurs bearing localities discovered in the Ili River Basin in the foothills of Dzhungur Alatau, in the center of the historical region Zhetysu (Semirechie), in 1925-1927 are among the first occurrences for dinosaurs discovered in Asia. Preliminary identifications of dinosaurian remains from the Zhetysu localities, reviewed by Nesov (1995a), included Sauropoda, Tyrannosauridae, Hadrosauridae, Ankylosauridae, and possibly Ceratopsidae. The only previously described specimen from this assemblage is a tibia attributed to cf. Ceratopsia

by Riabinin (1939) from the Kara-Cheku locality. This bone is considered currently as Dinosauria indet. We describe here the most important find from this fauna to date, a partial tyrannosaurid dentary collected by a team from the Institute of Zoology of the Kazakh Academy of Sciences at the Kara-Cheku locality in 1950. This specimen can be confidently identified as a derived tyrannosaurine based on the incrassate teeth and the small first alveolus. This is the first record of a tyrannosaurine from the Late Cretaceous of Kazakhstan and Middle Asia. The age of Zhetysu dinosaur fauna is possibly Campanian or Maastrichtian.

The complete text is on this link.http://www.zin.ru/journals/trudyzin/doc/vol_316_2/TZ_316_2_Averianov.pdf

alioramus_alti_skullAlioramus Skull cast replica Scientific Name: Alioramus alti 

Cretaceous

Measures: 28" L x 9" W 

Specimen: Wyoming Dinosaur Center 

Location: Mongolia 

Formation: Nemegt 

Alioramus is a genus of tyrannosaurid theropod dinosaur from (Late Cretaceous) Asia. 

Type specimen: Alioramus remotus 

This link has another (artistisc) illustration of an Alioramus reconstruction . http://en.wikipedia.org/wiki/File:Alioramus_BW.jpg

Alioramus was a genus of theropod dinosaurs that lived during the Cretaceous. The systematic paleontology of Alioramus is:

Dinosauria Owen 1842Saurischia Seeley 1887Theropoda Marsh 1881Tyrannosauroidea Osborn 1906Tyrannosauridae Osborn 1905Alioramus Kurzanov 1976Alioramus remotus (type) Kurzanov 1976A. altai Brusatte et al. 2009

Alioramus remotus is the type species. The holotype (PIN 3141/1) is a partial skeleton. It was found in the Nemegt Formation in Omnogov, Mongolia. This fossil specimen dates to the Maastrichtian age (70.6 - 65.5 million years ago) of the Cretaceous. The holotype (IGM 100/1844) of Alioramus altai also dates to the Maastrichtian. This fossil is a partial skull. It was discovered in the Nogon Tsav Formation at Nogon Tsav in Bayankhongor, Mongolia. [Note - The source of this information is The Paleobiology Database.]Stephen L. Brusatte, Thomas D. Carr, and Mark A. Norell wrote an article titled The Osteology of Alioramus, A Gracile and Long-Snouted Tyrannosaurid (Dinosauria: Theropoda) from the Late Cretaceous of Mongolia. It was published in 2012 in the Bulletin of the American Museum of Natural History, Number 366: 1-197. 

The abstract is on this link.http://www.bioone.org/doi/abs/10.1206/770.1

The osteology of Alioramus, a gracile and long-snouted tyrannosaurid (Dinosauria, Theropoda) from the late Cretaceous of Mongolia. (Bulletin of the American Museum of Natural History, no. 366)Brusatte, Stephen.; Carr, Thomas D.; Norell, Mark.; Mongolian-American Museum Paleontological Project.; Mongolyn Shinzhlėkh Ukhaany Akademi.URI: http://hdl.handle.net/2246/6162Date: 2012-02-29Abstract:The late Cretaceous tyrannosaurid theropod Alioramus has long been one of the most puzzling large carnivorous dinosaur taxa, largely because for several decades it has been represented only by a single, fragmentary specimen that seems to represent a long-snouted and gracile individual but is difficult to interpret. The discovery of a substantially complete skeleton of Alioramus at the Tsaagan Khuushu locality in the Maastrichtian Nemegt Formation of Mongolia, recovered during the 2001 American Museum-Mongolian Academy of Sciences expedition and described as a new species (Alioramus altai) in 2009, definitively shows that this mysterious taxon is a distinct form of longirostrine tyrannosaurid that lived alongside the larger and more robust Tarbosaurus. Here we describe and figure this remarkably preserved skeleton in detail. We provide exhaustive descriptions and photographs of individual bones, and make extensive comparisons with other tyrannosauroids. This monographic description provides further evidence that Alioramus is an unusual long-snouted, gracile, and slender-limbed taxon with an unprecedented degree of cranial ornamentation among tyrannosaurids and an extremely pneumatized skeleton. Anatomical comparisons indicate that the long skull of Alioramus is an autapomorphic feature that is proportionally longer (relative to femur length) than in any other known tyrannosaurid specimen, including juveniles, and that Alioramus is morphologically distinctive relative to similarly sized individuals of the contemporary and sympatric Tarbosaurus. The holotype specimen of A. altai belongs to a young individual, and many differences between it and the other known specimen of Alioramus (the holotype of A. remotus) may represent ontogenetic variation. The unusual longirostrine skull of Alioramus was largely produced by lengthening of the snout bones (maxilla, nasal, dentary, lacrimal, jugal), rather than the orbiotemporal bones (frontal, postorbital, squamosal, quadratojugal). The long snout, gracile skull bones, comparatively small attachment sites for jaw muscles, and lack of interlocking sutures and a robust orbital brow would have precluded the holotype individual from employing the characteristic "puncture-pull" feeding style of large-bodied adult tyrannosaurids, in which the muscular jaws, thick teeth, and interlocking sutures enabled individuals to bite with enough force to fracture bone. Whether adult Alioramus could utilize "puncture-pull" feeding awaits discovery of mature individuals of the genus. The coexistence of the long-snouted Alioramus and robust and deep-snouted Tarbosaurus, which are found together at the Tsaagan Khuushu locality, demonstrate that multiple large tyrannosaurids were able to live in sympatry, likely because of niche partitioning due to differences in craniofacial morphology and functional behavior.

Alioramus altaiUn nouveau membre de la famille des Tyrannosaures a été décrit en 2009. Mais, cette fois, il ne s’agit pas d’un gigantesque prédateur aux mâchoires impressionnantes. Alioramus altai jouerait plutôt dans le camp des poids

plumes.Il s’agit en effet d’un petit cousin à la morphologie inhabituelle.

Alioramus était jusqu’à présent connu par quelques fossiles fragmentaires et brièvement décrit en 1976.Mais, un nouveau fossile très bien conservé a permis aux paléontologues d’en apprendre plus sur ce petit tyrannosaure qui vivait au Crétacé supérieur en Asie.

Le squelette a été mis au jour en Mongolie dans le désert de Gobi. C’est déjà là qu’avait été découvert Tarbosaurus, un grand tyrannosaure qui ressemble comme un jumeau à Tyrannosaurus Rex.

En comparaison, Alioramus est deux fois moins grand que Tarbosaurus, soit une longueur d’un peu moins de 5 m de long pour un poids estimée à 369 kilos.

Cependant, il ne s’agit pas d’un adulte car le spécimen est mort prématurément à l’âge de 9 ans. D’après les chercheurs, il s’agit d’un adolescent.La taille du spécimen découvert correspond à environ 85% de la taille adulte.

Alioramus. © American Museum and Natural History

Outre sa petite taille pour un Tyrannosauridé, Alioramus arbore sur son museau huit petites cornes d’une dizaine de centimètres.C’est une première pour les membres de cette famille.

L’ensemble du squelette montre un théropode gracile, au crâne assez fin. Cependant, il ne faut pas s’y tromper, il s’agit bien d’un prédateur carnivore comme l’attestent ses petites dents fines mais bien aiguisées.

Illustration du crâne. © American Museum and Natural History

Comme ses grands cousins, ses membres antérieurs sont extrêmement courts et équipés de trois doigts ornés de belles griffes bien incurvées.

Il est évident, qu’étant donné sa petite taille, il ne chassait pas les mêmes proies que Tarbosaurus.Sur le même territoire, chaque prédateur devait occuper sa propre niche écologique et chasser des proies très différentes.

Cette découverte prouve que tous les Tyrannosauridés n’ont pas évolué de la même manière et que tous n’ont pas « opté » pour le gigantisme.

Classification: Saurischia Theropoda Tyrannosauria Tyrannosauridae Tyrannosaurinae

V. Battaglia (27.10.2009) Source: (AMNH)

Tyrannosauridés < Raptorex et l'évolution des Tyrannosauridés <

alioramus_skeletonReconstruction  Alioramus sp  Alioramus cast replica Location: Mongolia  Formation: Nemegt  Cretaceous 

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teratophoneus_curielJuvenile Tyrannosaur Skull cast replica Scientific Name: Teratophoneus curriei Location: SE Utah USA  Formation: Kaiparowits  CretaceousMeasures: 25"L x 16" T x 10.5"W 

Teratophoneus curriei Juvenile Tyrannosaur Skeleton cast replica  Scientific Name: Teratophoneus curriei Location: SE Utah USA  Formation: Kaiparowits  Age: Cretaceous Measures: 17.5' Long Specimen: Utah Museum of Natural History

Tarbosaurus-skeleton- Mongolia

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tarbosaurus_skull cast Tarbosaurus the T.rex from Asia.

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Dinosauriërs kauwden anders10 juni 2010 Tim Kraaijvanger 0

Niet iedere dinosaurus kauwde op dezelfde manier. Dit blijkt uit een onderzoek van Manabu Sakamoto van de universiteit van Bristol. Hij onderzocht de tanden en spieren van verschillende dino’s. De uitgestorven haai Carcharodon megalodon had de grootste bijtkracht.

Sommige vleesetende dinosauriërs hadden een zwakke bijtkracht, maar konden wel snel kauwen, zoals de Velociraptor.

Andere dino’s – zoals de Tyrannosaurus Rex – waren in staat om sterke en efficiënte happen te nemen.

Volgens Sakamoto had een dinosaurus niet veel tanden nodig voor een grote bijtkracht. Zo hadden Tyrannosauriërs, allosauriërs en ceratosauriërs een grote bijtkracht, maar niet zoveel tanden. Ook apart: de Coelophysis en de Megapnosaurus konden met de tanden achterin hun bek veel kracht zetten, terwijl de voorste tanden hier niet in slaagden.

Stephen Wroe van de universiteit van Zuid-Wales meent dat de Tyranossaurus Rex de grootste bijtkracht had van alle dino’s, namelijk 3,1 ton. Groter dan de bijtkracht van de witte haai (1,8 ton). Een mens heeft een bijtkracht van 0,09 ton, oftewel ruim tachtig kilo.

De uitgestorven haai Carcharodon megalodon is volgens Wroe de winnaar op het gebied van bijtkracht. ‘Big Tooth’ had een overweldigende bijtkracht van 18,2 ton.

T. rex had een van de sterkstee beten 29 februari 2012 Caroline Kraaijvanger 2

De T. rex was het landdier met de sterkste kaken ooit. Geen enkel levend of uitgestorven landdier kan eraan tippen.

Dat schrijven de onderzoekers in het blad Biology Letters. Ze baseren hun conclusie op computermodellen waarmee ze de kaakspieren van de Tyrannosaurus rex reconstrueerden en ze vervolgens in actie konden zien.

MensEn het bleef niet bij de T. rex. De onderzoekers bestudeerden ook de kaken van mensen, de alligator, een jonge T. rex en de Allosaurus (ook een vleesetende dinosaurus). Met behulp van de computer vergrootten ze de schedels van deze soorten net zolang tot ze zo groot waren als die van een T. rex. De kracht van de kaakspieren werd daarmee ook groter. Maar niet zo groot als die van de T. rex. De onderzoekers leiden daaruit af dat de T. rex wel de sterkste beet van alle levende en uitgestorven landdieren moest hebben.

Veel sterkerUit het onderzoek blijkt ook dat de kaakspieren van de T. rex veel sterker waren dan gedacht. Men vermoedde altijd dat de beet van de dinosaurus een kracht van 8000 tot 13.400 Newtons had. Dat lijkt veel, maar van een beest van 6000 kilo mogen we toch wel wat meer verwachten, zo vermoedden de onderzoekers. En dus pakten ze de computermodellen er weer bij om de kracht van de T. rex nog preciezer te kunnen achterhalen. Een lastige klus, want niemand weet precies hoe de spieren van de dino eruit zagen. Toch durven de onderzoekers te stellen dat de kaakspieren een kracht tussen de 20.000 en 57.000 Newtons had.

JonkieDe T. rex werd niet met die kracht geboren, zo blijkt uit het onderzoek. De jonge T. rex had een aanzienlijk zwakkere beet. Waarschijnlijk had deze dan ook een iets ander dieet dan de volwassen T. rex.

“Onze resultaten laten zien dat de T. rex een enorm sterke beet had,” vertelt onderzoeker Karl Bates. “En dat maakt het tot één van de meest gevaarlijke roofdieren die ooit op onze planeet rondliepen.”

Krokodil heeft sterkste absolute beet 15 maart 2012 Marleen de Roode 4

De krokodil heeft de sterkste absolute * beet van heel het dierenrijk. Daarmee stoot hij zelfs de Tyrannosaurus rex van zijn troon.

Een paar weken geleden bleek nog uit onderzoek dat de Tyrannosaurus Rex de sterkste beet had. Uit een nieuw onderzoek lijkt de reusachtige dinosaurus van zijn troon gestoten door niemand minder dan de krokodil.

Sterkste beetWetenschappers van de Florida State University maten de bijtkracht en de druk van de tanden van 23 volwassen krokodillen. De krokodillen waren onder andere alligators, kaaimannen en gangesgavialen. De zoutwaterkrokodil bleek de sterkste bijter te zijn, met een kracht van 1678 kilo per 2.54 centimeter (1 inch). Ook brak het beest een record met een druk van meer dan 163.293 kilo per vierkante inch. De bijtkracht van de grootste, uitgestorven krokodil is 10.432 kilo, twee keer zo veel als de bijtkracht van de T. rex.

EvolutieDe onderzoekers kwamen er achter dat de bijtkracht een wisselwerking heeft met de grootte van het lichaam, maar weinig wisselwerking met de vorm van de tanden, de vorm van de kaak of kaakkracht. Dit resultaat suggereert dat toen krokodillen eenmaal hun toonaangevende kracht geëvolueerd hadden, verdere modificaties voornamelijk veranderingen in lichaamsgewicht en het doorbreken van tanden en kiezen waren.

Het onderzoek geeft wetenschappers beter inzicht in de relatie tussen anatomie, biomechanica, prestatievermogen en ecologie van levende en fossiele krokodillen. Op basis daarvan kunnen de geheimen van hun 85 miljoen jaar lange succes worden ontrafeld.

Het dier met de sterkste relatieve ( allometrie ) beet

http://www.scientias.nl/uitgestorven- megapiranha -had-krachtigere-beet-dan-t-rex/77938

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Albertosaurus Albertosaurus is a Cretaceous carnivore named for the Canadian province of its discovery It was first discovered by J.B. Tyrell in 1884, and was officially identified as a species in 1905.

As a member of the family Tyrannosauridae, Albertosaurus is a relative to the T. Rex. They share many physical similarities, including a large skull, small forelimbs, and powerful hind legs. Albertosaurus, however, was smaller than the T. Rex, and predated it by a few million years. They were probably very fast runners, and could recovered from stumbles and falls easier than their larger relatives.

Albertosaurus had quite a few teeth. 14-16 on the lower jaw, and 17-19 on the upper. Though they had only one row of teeth at a given time, there was always a replacement growing in the jaw in case a tooth fell out!

We actually know quite a bit about the Albertosaurus, as there have been fossils of over 30 different individuals discovered. Not only are there numerous fossils, but the individuals that they represent span a large age range. That, combined with the fact that many of the fossils were found on one site, suggests that the Albertosaurus lived

in large pack groups.

There is a bit of confusion surrounding the species within the Albertosaurus genus. 

A. sarcophagus has long been considered the type species, but for a long time a second species A. libratus was also classified with the genus.Studies have been done to determine whether these two Dinosaurs belong so closely related, and now there are many who have changed A. libratus to Gorgosaurus libratus.Albertosaurus libratus (Lambe 1914) Russell 1970: ---> Albertosaurus genus = Gorgosaurus libratus (Lambe 1914)

http://www.dinosaur-world.com/tyrannosaurs/albertosaurus_sarcophagus.htmAlbertosaurus sarcophagus

Albertosaurus arctunguis (Parks, 1928).Skull length : up to 1 m.; Total length : 8 m.; Hip height : 2.5 m.; Weight : 2 tonhttp://nl.wikipedia.org/wiki/AlbertosaurusAlbertosaurus arctunguis(Parks 1928):= young A. sarcophagus, = Deinodon arctunguis ( Kuhn 1939)

Name Means: "Alberta lizard" Length: 26 feet (8 m) Diet: Carnivore (Meat-Eater) Time: Late Cretaceous Location: South-western CanadaAlbertosaurus was a slightly older relative of Tyrannosaurus and was very similar in appearance. Tyrannosaurus lived between 70 and 65 million years ago; Albertosaurus roamed the North American late Cretaceous world between 75 and 70 million years ago. Like Tyrannosaurus, Albertosaurus was a huge biped with two-fingered hands and thin plates of bone covering some of its skull openings. Albertosaurus was smaller and had a narrower skull than Tyrannosaurus, and its eyes looked more to the side. 

In front of its eyes, Albertosaurus had a pair of small, blunt horns, which it may have used for sexual display. Perhaps because its body was smaller, Albertosaurus's skeleton was more gracile than that of Tyrannosaurus. It was also a faster mover than its more cumbersome successor. 

Searches of fossil-bearing beds in south-western Alberta have yielded some amazing discoveries, including a number of nearly complete skeletons of juvenile Albertosaurus. While adult Albertosaurus had rather stout bones in their hindlimbs, the hindlimbs of very young specimens were remarkably slender. In some cases, several Albertosaurus skeletons-at different stages of growth-have been found together. 

On the strength of these finds, some researchers have suggested that these dinosaurs traveled as family groups. However, there is no conclusive evidence that skeletons found together were from animals that actually lived together as a group. 

Albertosaurus is the best known of all tyrannosaurids. Recent discoveries include wishbones-a feature it shared with other advanced theropods as well as with birds. Many museum specimens of Tyrannosaurus have filled in gaps in our knowledge of the larger dinosaur with information taken from Albertosaurus.

Albertosaurus

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Gorgontosaurus,

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Rex.jpghttp://nl.wikipedia.org/wiki/Categorie:Tyrannosaurus

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dinosaur bone mineralization in vascular canal.

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Proceratosaurus T rexProceratosaurus compared with T rex

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Yutyrannus huali phylogeny.jpgA simplified cladogram showing the systematic position ofY. huali among the Tyrannosauroidea. Silhouettes indicate body size andpossible extent of plumage. Different tyrannosauroids seem to have attainedgigantic body size independently in the Early and Late Cretaceous, but only inthe Early Cretaceous is there direct evidence of a gigantic form with anextensively feathered integument. This may reflect the relatively cold climate ofthe middle Early Cretaceous. //

Yutyrannus Scott Hartman http://skeletaldrawing.blogspot.com/2012/04/ioyutyrannus.html

Yutyrannus huali.jpghttp://archosaurmusings.wordpress.com/2012/04/04/the-giant-feathered-tyrannosaur-yutyrannus-huali/

Figure 1 | Yutyrannus huali (ZCDM V5000 and ZCDM V5001).a, Photograph of the slab preserving ZCDM V5000 and ZCDMV5001. b, Linedrawing of the slab. Abbreviations: cav, caudal vertebra; cev, cervical vertebra;dr, dorsal rib; dv, dorsal vertebra; ga, gastralia; lfe, left femur; lfi, left fibula; lh,left humerus; lil, left ilium; lis, left ischium; lm, left manus; lp left pes; lr, leftradius; ls, left scapula; lt, left tibiotarsus; lu, left ulna;ma, mandible; pu, pubis; rc,right coracoid; rfe, right femur; rh, right humerus; ril, right ilium; rm, rightmanus; rp, right pes; rr, right radius; rs, right scapula; rt, right tibiotarsus; ru,right ulna; sk, skull; sy, synsacrum.

Paper ; http://www.xinglida.net/pdf/Xu_et_al_2012_Yutyrannus.pdf

Yutyrannus huali 2.jpghttp://archosaurmusings.wordpress.com/2012/04/04/the-giant-feathered-tyrannosaur-yutyrannus-huali/Yutyrannus hualihttp://www.wired.com/wiredscience/2012/04/yutyrannus-huali-feathers/

http://www.wired.com/search?query=Dinosaurs+&cx=010858178366868418930%3Afk33zkiunj8&cof=FORID%3A9&ie=UTF-8

http://www.nature.com/nature/journal/v484/n7392/full/nature10906.htmlhttp://whyevolutionistrue.wordpress.com/2012/04/05/a-huge-feathered-dinosaur/http://blogs.discovermagazine.com/notrocketscience/2012/04/04/yutyrannus-a-giant-tyrannosaur-with-feathers/http://blogs.discovermagazine.com/loom/2012/04/04/the-one-ton-turkey-further-adventures-in-slow-cooked-science/

http://nl.wikipedia.org/wiki/Yutyrannushttp://www.scientias.nl/enorme-gevederde-dinosaurus-ontdekt-2/60141http://www.hln.be/hln/nl/961/Wetenschap/article/detail/1418998/2012/04/04/Gigantische-dino-met-veren-was-familie-van-T-Rex.dhtml?show=reacthttp://dieren.blog.nl/natuur-en-wetenschap/2012/04/04/gevederde-tyrannosaurier-ontdekt-in-chinahttp://historiek.net/actueel/fossielen-onbekende-gevederde-dinosaurus-ontdekt-6148http://nos.nl/artikel/359084-gevederde-tyrannosaurus-ontdekt.htmlhttp://www.parool.nl/parool/nl/265/GEZONDHEID-WETENSCHAP/article/detail/3236060/2012/04/04/Gigantische-gevederde-dino-gevonden-in-China.dhtmlhttp://www.eosmagazine.eu/home/ctl/Detail/mid/485/xmid/4844/xmfid/12.aspx

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