The Dinosaurus

Dinosaurs are an ancient group of animals from Dinosaurian clans. Dinosaurs first appeared in the Triassic period, some 230 million years ago, and are the dominant vertebrates for 135 million years, beginning from the Jurassic period (about 201 million years ago) to the end of the Cretaceous period (65 million years ago), and Then perished as a result of the Kapur-Paleogen extinction event before the Mesozoic era. Studies of dinosaur fossils show that bird species evolved from theropod dinosaurs during the Jurassic period, and consequently, thousands of species of living birds have now been classified as sub-groups of dinosaurs by paleontologists. [1] Some surviving birds from extinction 66 million years ago and their descendants continue the survival of dinosaurs until now

Dinosaurs can be categorized into different groups of animals from the point of view of taxonomy, morphology, and ecology. More than 9,000 bird species are the most diverse types of vertebrate dinosaurs, in addition to the fish perciform. [3] Using fossil evidence, paleontologists have identified more than 500 different dinosaur genera, [4] and more than 1,000 species that are not the same as non-avian dinosaurs. [5] The type of dinosaurs on every continent can be determined through living species or through fossil remains. [6] Most of them are herbivores, while the rest are carnivores. Most of the living dinosaur descendants are bipedal (bipedal), but most extinct dinosaurs are quadrupedal (four-legged) species. The elaborate display structures such as horns or crests are commonly owned by all groups of dinosaurs, and some extinct groups also have distinctive bony structures such as spines and sharp spines. Research shows that laying and nesting is another characteristic of all dinosaurs. Although modern bird species are generally small in size because they adapt to flying abilities, most large prehistoric dinosaurs - the largest of which are Amphicoelias fragilimus from sauropods, with a length of 60 meters (200 feet) and a height of 10 meters (30 feet) weighing 150 Ton. [7] However, the notion that non-avian dinosaurs are generally gigantic is a misunderstanding; Many small dinosaurs, such as Xixianykus, are only 50 centimeters (20 inches) in length.