Dinosaur SVG (Latin Dinosauria from δεινός “terrible, dangerous” + σαῦρος “lizard”) – a squad of terrestrial vertebrates that dominated the Earth in the Mesozoic era – for more than 160 million years, from the late Triassic period (about 225 million years ago) to the end of the Cretaceous period (66 million years ago), when most of them began to die out during the large-scale extinction of animals and many plant varieties in a relatively short geological period of history. Dinosaur SVG fossils have been found on all continents. Nowadays, paleontologists describe more than 500 different genera and more than 1000 different species, which are clearly divided into two groups: poultry and lizard pellets.
Dinosaur SVG History
Giant bones, sometimes found in the ground, in antiquity were considered the remains of heroes of the Trojan War, in the Middle Ages and up to the XIX century – the remains of giants, mentioned in the Bible and who died during the Flood, in the Far East they were considered the bones of dragons and attributed to them healing properties.
In 1824, the president of the Royal Geological Society, William Buckland, made a report on the discovery made in 1815 in the Jurassic shales of Stonesfield (Oxfordshire County), consisting of several bones and a fragment of a “pre-flooded” animal. With the help of a prominent comparative anatomy specialist Georges Cuvier, Buckland classified the find as the remains of a giant predatory lizard (lat. sauria) and, accordingly, called it a megalosaurus – a “giant lizard”.
In 1826, Gideon Mantell, a surgeon from Lewis (Sussex County), a full member of the Linnaean Society, similarly presented the teeth he had found in the Geological Society of a previously unknown species, to whom he named the iguanodon (letter “iguanodon”) for the resemblance of the tooth to that of the iguana lizard. In 1833, he also described the Gileosaurus, a representative of the armored lizards of the Anquilosaurs.
In 1842, the English biologist Richard Owen, noting the undoubted similarity between these three species and their difference from modern reptiles, singled them out as a special subcontractor, calling it Dinosauria (“terrible lizards”).
The discovery of the well-preserved gadrosaurus skeleton in the USA in 1858 overturned the idea of dinosaurs as four-legged animals, showing that the dinosaurs could walk on both legs. In the next few decades, most of the major dinosaur groups were discovered; an important contribution was made by American palaeontologists Gophonyilus Marsh and Edward Cop, who discovered and described a total of 142 new species, including the apatosaurus and brontoseaurus (which later became part of the same genus), diplodocus and stegosaurus, monoclone, triceratops, and others. The accumulation of material led to the division of dinosaurs into poultry and lizard families (1887).
Within the limits of the first half of the twentieth century the most part of scientific community mistakenly believed that dinosaurs were bulky, languid animals. The majority of researches spent since 1970, however, have specified that dinosaurs were active animals with the raised metabolism and numerous features for social interaction.
In 1964, the discovery of the deinonikha produced a new scientific revolution, as the structure of the dinosaur was clear that he moved relatively quickly, which concluded that he was warm-blooded. The idea of warm-bloodedness led to a review of old notions not only of physiology, but also of dinosaur behaviour, which was confirmed in 1979, when evidence of parental instinct and social behavior of lizards (nursing, protection and feeding of cubs) was obtained. Finally, the comparison of the upper extremities of a deinoniac with a bird’s wing made us suppose their closeness and origin of birds from dinosaurs (or even belonging to this group in general), which was proved by the discovery of plumage traces in a number of dinosaurs. In 2005, scientists managed to isolate collagen from the surviving soft tissues of tyrannosaurus and use its chemical composition as another proof of the relationship between dinosaurs and modern birds.
A number of scientists claim that about a third of the dinosaur species described above did not exist. Scientists thought that the dinosaurs described above were unknown at different stages of development. A large-scale study conducted by other scientists showed that almost 50% of all dinosaur species were misnamed.
Currently there are two opposite trends in the systematics of dinosaurs. While some paleontologists continue to crush the existing taxa, identifying new genera and species from the existing ones, others question the correctness of the previously described species. In 2007, Jack Horner published an article in which he stated that Dracorex hogwartsia, Stygimoloch spinifer and Pachycephalosaurus wyomingensis are three different age stages of the same species. In 2009, Jack Horner concluded in his study of the skull of Nanotyrannus that this dinosaur is actually a young Tyrannosaurus. In 2010, the Journal of Vertebrate Paleontology published an article by palaeontologists from Montana State University, which also states that Triceratops and Torosaurus are different stages of growth of individuals of the same species. In the same year, other scientists at Yale University described a new genus of dinosaurs, Mojoceratops, whose bones had previously been classified as Chasmosaurus.