Upper Cretaceous 68-65 mya
|Skeleton at the National Museum |
of Natural History, Washington, D.C.
Tyrannosaurus was a bipedal carnivore with a massive skull balanced by a long, heavy tail. Compared to the large and powerful hind limbs, its forelimbs were small, but powerful for their size. They had two clawed digits.
There is discussion as to whether it was a hunter or a scavenger. Like most dominant meat-eaters of today, such as lions and hyenas, Tyrannosaurus might have been both. It had a very strong jaw, and its bite power could snap the bones of other dinosaurs.
More than 30 specimens of Tyrannosaurus Rex have been found. Some of them are nearly complete skeletons, and soft tissue and proteins have been reported in at least one of these specimens. Research is done on its biology, life history and biomechanics. The feeding habits, physiology and potential speed of Tyrannosaurus ex are some topics. Some scientists think Tarbosaurus bataar from Asia is a second species of Tyrannosaurus, but others think Tarbosaurus is a separate genus.
The estimated size of this dinosaur has changed many times. Packard and colleagues tested dinosaur mass calculations on elephants. They decided that dinosaur estimations are flawed and produce results which were too high. Thus, the weight of Tyrannosaurus could be much less than usually estimated.
Although other theropods rivalled or exceeded Tyrannosaurus rex in size, it was the largest known tyrannosaurid and one of the largest known land predators. It was up to 12.3 m (40 ft) in length, up to 4 metres (13 ft) tall at the hips, and up to 6.8 metric tons (7.5 short tons) in weight. By far the largest carnivore in its environment, Tyrannosaurus rex was a top predator, probably preying on hadrosaurs and ceratopsians, and/or a scavenger. The debate over Tyrannosaurus as apex predator or scavenger is among the longest running in paleontology.
For a long time, Tyrannosaurus was the largest known carnivorous dinosaur. Recently, skeletons of other, slightly larger, carnivores have been found, such as Giganotosaurus, Spinosaurus, Carcharodontosaurus and Mapusaurus. Skeletons of Tyrannosaurus were found on the North American continent, but relatives, such as Tarbosaurus or Alioramus, have been found in Asia.
The largest known Tyrannosaurus rex skulls measure up to 5 feet (1.5 m) in length. Large openings ('fenestrae') in the skull reduced weight and gave places for muscle attachment, as in all carnivorous theropods. But in other respects Tyrannosaurus's skull was significantly different from those of large non-tyrannosaurid theropods. It was extremely wide at the rear but had a narrow snout. This permitted good binocular vision. The skull bones were massive. Some bones were fused, preventing movement between them; but many were pneumatized, with a "honeycomb" of tiny air spaces. This may have made the bones more flexible as well as lighter. These features are part of the tyrannosaurid trend towards an increasingly powerful bite. Its bite easily surpassed that of all non-tyrannosaurids.
The tip of the upper jaw was U-shaped (most non-tyrannosauroid carnivores had V-shaped upper jaws), which increased the amount of tissue and bone a tyrannosaur could rip out with one bite, although it also increased the stresses on the front teeth.
First Tyrannosaurus DiscoveryEdit
The earliest Tyrannosaurus skeletons were found in 1902 by Barnum Brown. Henry Fairfield Osborn, president of the American Museum of Natural History, named the species Tyrannosaurus rex (meaning "tyrant lizard king") in 1905. The most complete skeleton was found in 1990 in South Dakota and named "Sue" after its finder, Susan Hendrickson.
Tyrannosaurus has become well known. Many movies and television shows have featured it, such as Jurassic Park. Its skeletons are popular exhibits in many museums.
After four years of preparation, Jane went on display at Rockford, Illinois in the Burpee Museum of Natural History. Some paleontologists think Jane was a juvenile about 11 years old at its time of death. Its fully restored skeleton measured 6.5 metres (21.5 ft) long, about half as long as the largest known complete T. rex specimen, which measures 13 m (42.6 ft) long. The weight of the specimen in life was probably nearly 680 kg (1,500 lbs). Its large feet and long legs indicate it was built for speed and could possibly run as fast as 20–30 miles per hour. Its lower jaw has 17 curved, serrated teeth.
Despite having a typically female name, Jane's sex is unknown—the specimen was named after Burpee Museum benefactor Jane Solem.
In 2017, fossilized skin had been found. However, Tyrannosaurus Rex had more in common with the feathered Dilong and Yutyrannus. Scientists suggest that it had a feathered cape. New fossil evidence shows that Tyrannosaurus Rex had fossilized bristle feathers on it's back and shoulders. It's bristle feathers may have been used to attract mates.
Thanks to scientists, we know what the color pattern looked like thanks to melanin. It was revealed that Tyrannosaurus Rex would have had patches brown, black, and grey and had orange and yellow rims that is used for communicating.
A team of researchers scanned the facial bones of tyrannosaurs and found out that their faces were covered in scales, however they may have included lips. We often see some dinosaur teeth sticking out of their mouths but scientists suggest that the teeth were covered by lips like we see it on modern day lizards.
Tyrannosaurus Rex's bite force is 8,000 lbs which is more powerful than Megalodon's bite. Tyrannosaurus Rex has the strongest bite than any mammal or animal.
Using 3-D technology ,scientists accurately estimate the mass of the Tyrannosaurus rex. It turns out that the Tyrannosaurus was bigger, muscular, and stronger than we even thought.
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