The self of the heavens has billions of clones

Chapter 141

The team at the University of Alberta in Canada stated that the tyrannosaurus named "Scotty" was 13 meters long and probably weighed more than 8800 kilograms, surpassing all carnivorous dinosaurs discovered in the past .

On May 2019, 5, the skeleton of the world's largest Tyrannosaurus rex "Scotty" was exhibited in Saskatchewan, Canada. It was 18 meters long and weighed over 13 tons during its lifetime, which was 8.8 times heavier than the previously considered largest Tyrannosaurus rex. %.

Forelimb
Like other tyrannosaurids, Tyrannosaurus rex has very small forelimbs, only 22% of the length of its hind limbs. The average length of an individual is only about 80 centimeters. Compared with the huge size and hind limbs of Tyrannosaurus rex, the forelimbs are very small, equivalent to a Adult arms.Their arms are very thin and the long skull of the small Tyrannosaurus rex puts its forelimbs further back. The pair of forelimbs cannot reach forward to reach its mouth, nor can it touch its own mouth, nor can it touch its own body. The feet may serve merely as balancing tools to balance their huge heads.

head
Judging from the shape of the skull of Tyrannosaurus rex, its upper jaw is wide and its lower jaw is narrow. When biting, the forces exerted by the upper and lower jaw teeth are not completely opposite, which is conducive to breaking bones.The teeth of Tyrannosaurus rex are cone-shaped like bananas and are suitable for crushing bones, while the teeth of most carnivorous dinosaurs are mostly used for piercing and cutting.Its skull structure suggests that Tyrannosaurus rex's hunting behavior may have been different from that of most theropod dinosaurs.

Generally speaking, large carnivores will choose prey that is about the same size as themselves or smaller.Animals that hunt alone tend to choose prey that are similar in size to themselves or smaller; creatures that hunt in groups can often hunt prey that is much larger than themselves. A new paper in 2014 shows that the bite force of different adult Tyrannosaurus rex individuals ranges from 10 to 20 Newtons. The average individual bite force is about 10 tons+.

Figure
In terms of body length, most carnivorous dinosaurs can exceed Tyrannosaurus rex, including Carcharodontosaurus, Barbarosaurus, Kuizhousaurus, and Sauronosaurus. However, Tyrannosaurus rex's body width, cervical vertebrae width, leg length, pelvis size, and shoulder blade size are far different. It far exceeds almost all Allosaur superfamily dinosaurs such as Maposaurus and Kuizhousaurus, and has the largest and thickest head, cervical vertebrae, torso and hind limbs among the carnivorous dragons. The foot suborders (such as Ceratosaurus, Allosaurus, Megalosaurus, Yongchuanosaurus, etc.) only have less than 50% of the weight of Tyrannosaurus rex, and some sturdy carnivorous dragons (such as Tarbosaurus, Explosaurus) are only The same body length is 75%-80% of the body weight of Tyrannosaurus rex.Although members of the Carcharodontosauridae family have a slight advantage in length compared to the Tyrannosaurus family, they are not comparable to the Tyrannosaurus family in terms of stoutness. For example, Carcharodontosaurus and Giganotosaurus are both close to Tyrannosaurus rex in length, but But it is not as good as Tyrannosaurus rex in terms of weight and height.Among the carnivorous dinosaurs, only Manosaurus and Kuizhousaurus have a body mass index that reaches or approaches 90% of Tyrannosaurus rex.The skeleton of Tyrannosaurus rex is also very thick. Although reptiles will continue to grow as long as they survive, this does not mean that reptiles will always become taller and longer. The growth cycle of Tyrannosaurus rex ends at the age of 19, and will not exceed 21 at the latest. Years old, when the growth cycle of Tyrannosaurus rex ends, although Tyrannosaurus rex will continue to grow, it will neither grow longer nor become taller. Its skeleton will become thicker and the overall look will be stronger.This is why the 28-year-old "Su" is only 12.2 meters tall, but can compete with mor14, ucmp1126 and others who are over 137538 meters tall to be the largest tyrannosaurus ever discovered.

羽毛
In 2004, a study published in the scientific journal Nature described an early tyrannosauroid species, Diosaurus mirabilis, whose fossils were found in the Yixian Formation of China.Like many dinosaurs found in the Yixian Formation, Dilong's body had a covering that is thought to be primitive feathers.In addition, larger tyrannosaurs have also been found with feathers on their bodies, such as Yutosaurus Magnificent.

Tyrannosaurus rex and other tyrannosaur relatives are also speculated to have similar primitive plumage.But adult tyrannosaurid fossils found in Canada and Mongolia have rare skin marks, consisting of typical pebble-like scales.

It is also possible that some parts of the body of juvenile individuals were covered with primitive feathers, but they were shed when they grew up, and finally the body lacked spacers, as in many modern large mammals, such as elephants, hippopotamuses, and most rhinoceros.

According to Haldane's law, compared with the body volume, large animals have a smaller proportion of surface area, and the temperature of the heat they release is higher, while the temperature of the heat absorbed is lower; therefore, it is easier for the grown-up Tyrannosaurus to retain the heat in the body .

Large animals evolved in warm environments, and the heat-insulating feathers can trap excess heat in the body, causing hyperthermia.So large tyrannosaurs, such as Tyrannosaurus rex, may have lost their primitive feathers as they evolved to adapt to the warmer Cretaceous climate.

sexual dimorphism

As the specimens grew, scientists began to notice inter-individual variation in Tyrannosaurus and found that they could be divided into two patterns, or morphologies, similar to certain other theropod dinosaurs.One of the forms is thicker, while the other is more slender.Several morphological studies suggest that these two forms represent sexual dimorphism in Tyrannosaurus rex, with the stouter form generally thought to be a female.For example, the pelvis of several stout specimens appears to have been wider, possibly to accommodate an egg-laying tunnel.The herringbone on the first caudal vertebra of the stout form is obviously used to accommodate the birth canal of the reproductive system, and this feature also appears in crocodiles.

The evidence for sexual dimorphism is weakened.A 2005 study found that the original claim that the chevron-shaped bony features of crocodilians were sexually dimorphic was wrong, making the sex classification of tyrannosaurs with similar features controversial. "Su" has a full-sized chevron bone on the first caudal vertebra, and "Su" is a very stout individual, showing that this feature cannot be used to distinguish the two forms.Because T. rex specimens have been found from Saskatchewan to New Mexico, differences between individuals may be more indicative of geographic differences than sexual dimorphism.These differences may also be related to age, with stouter individuals likely being older individuals.

Only one T. rex specimen is now thought to actually belong to a certain sex. Soft tissue was preserved within several bones of the "B-Rex" specimen.Certain tissues were identified as medullary tissue, a tissue found only in birds that is a source of calcium that makes eggshells during spawning.

Because only females lay eggs, medullary tissue is only present in female birds; but during periods when females are producing hormones such as estrogen, males are also capable of producing medullary tissue.This evidence clearly shows that "B-Rex" was a female and died during spawning.

Recent studies have shown that crocodiles lack medullary tissue, while birds share it with theropod dinosaurs, further proving the evolutionary relationship between the two.

(End of this chapter)