Dinosaur: The most famous animal
Introduction
What is a dinosaur? Dinosaurs are among the most famous animals in the world, but paradoxically they are also among the least known. We only know of its existence by fossils, the hard parts of the body buried and stuck in the rocks for millions of years. The oldest dinosaurs fossils date from the early superior triassic, almost 230 million years ago. It is almost certain that its origin is much earlier. The supremacy of dinosaurs was complete until the end of the Cretaceous period, about 65 million years ago.
Developing
There were dinosaurs of all sizes: from small hunters not bigger than a cat to giants, the largest known creatures. They all seem to have had four limbs and one tail. Some walked and ran on their two hind legs, others over the four. Some did both! Unfortunately, fossils do not allow us to know the color of the skin or dinosaurs scales. The colors and forms drawn are conjectures. Some dinosaurs may have been opaque or brown green, such as crocodiles.
And some bright colors, such as some lizards or snakes. Recent discoveries made in China shake the ideas received a bit because they tend to show, at least in part, dinosaurs could have been covered with primitive plumage! Triceratops: a representation of a triceratops according to Joe Tucciarone. Paleontologists continue their research every day, both in the field and in their research centers, and each new kind of dinosaur is studied and then listed, and finally fossils are stored in museums or universities.
Despite this huge amount of work, it is very likely that we never know how many dinosaur species existed during their reign, which lasted around 165 million years. To date, there are a little less than 700 species listed. In 1819 in England, Gidéon tablecloth, doctor and paleontologist, discovered by chance in a forest the teeth fossils of an animal whose origin could not identify. MTRELL Then show them to other scientists who reject them when they are considered as from fish or mammals.
The eminent French anatomist Georges Cuvier even identifies them as rhino teeth. Tablell is convinced that it is not and warns that they look like the teeth of an iguana but twenty times larger. From this, it estimates that the size of the specimen is at least 20 meters long. Therefore, the animal was called Iguanodon (in Latin, iguana tooth). To record, some say that it was Maryann, Gideon Manter’s wife, who in fact discovered the first fossil. However, it was not until 1842 that the term dinosaur appeared for the first time.
It was Richard Owen, a doctor and paleontologist, a jury enemy of Gidéon Mantell, who proposed in 1841 during the "British Association of Sciences" the name of "Dinosauria" (from the Greek "Deinos", terrible and ‘Sauria’, reptile). With the help of Prince Alberto de Sajonia-Coburg-Gotha, the husband of Queen Victoria, established the London Natural History Museum, in South Kensington, to exhibit the National Dinosaur Fossils collection collection. Dinosaurs, reptiles especially. The term dinosaur encompasses a very diverse group of reptiles that dominated the earth during the Mesozoic era.
(Also known as high school) For three periods: Triassic, Jurassic and Cretaceous. There was no dinosaur that lived before or after this era. Dinosaur Geological Time Scale. Dinosaur Geological Time Scale. During the 165 million years that the existence of the group lasted (from -230 mA to -65 mA), it experienced great diversification. Paleontologists believe that there must have been several thousand dinosaur species, but unfortunately most of them have not left any trace or have not yet been discovered.
To date, there are a little less than 700 species listed. A recent American study concludes that about 71% of dinosaurs genres remain to be discovered, which would lead to 1850 the amount of dinosaurs species that have existed. The same study predicts that three quarters of the still unknown dinosaurs families will be identified within the next 100 years. Ichthyosaurus, a marine reptile who lived in the time of dinosaurs. Ichthyosaurus, a marine reptile who lived in the time of dinosaurs.
Contrary to popular belief, the names ‘marine dinosaur’ or ‘flying dinosaur’ are not correct. We talk about a marine reptile or a flying reptile, but be careful, these do not belong to the dinosaurs family. Dinosaurs are reptiles, but not all Mesozoic reptiles are dinosaurs! The ichthyiosaur was not a dinosaur: it was a marine reptile with fish body. It looked vividly to today’s dolphins. Pteranodon was not a dinosaur: it was a flying reptile. Pteranodon was not a dinosaur: it was a flying reptile.
Some common characteristics. Each dinosaur has its own characteristics, however, some of them are common to the entire group because they come from a common ancestor: arcosaur. Postosuchus. In primitive reptiles, the femur was horizontal and the limbs separated from the trunk did not allow the body to rise clearly above the ground. In dinosaurs, on the contrary, the articular head of the femur was well differentiated and moved into the animal’s body (mammal position).
This feature made it possible for certain dinosaurs to be placed vertically. The teeth of the dinosaurs were uniform: there was no type distinction as in mammals. Tyranosaur teeth. Egg setting is the only known reproduction mode today. Fossil dinosaur egg. The dinosaurs had a specific cavity in their skull: an additional bone window in the skull in front of the orbit, opening to which we gave the name of a pre orbital window or before orbital that distinguished them from other reptiles.
conclusion
Preorbital window of a dinosaur. The heart of the dinosaurs had four cameras, pumping blood in two stages from a single aorta (typical mammal features or birds and far away from those found in modern reptiles). This suggests the existence of a separate respiratory and circulatory system, which allows a much faster metabolism than that of cold -blooded animals. In other words, dinosaurs are very likely to be animals as active as modern animals.
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