Dinosaurs, (clade dinosaurs), the common name given to a group of reptiles, often very large, that first appeared about 245 million years ago (near the beginning of the Middle Triassic Era) and lasted about 180 million years flourished around the world. Most died out by the end of the Cretaceous period, about 66 million years ago, but several lines of evidence suggest that a lineage evolved into birds by about 155 million years ago.
The name dinosaur comes from the Greek words dinos (“terrible” or “terrifyingly great“) and sauros (“reptile” or “lizard“). English anatomist Richard Owen proposed the formal term Dinosauria in 1842 to include three giant extinct animals (Megalosaurus, Iguanodon, and Hylaeosaurus represented by large fossil bones) that had been unearthed at several locations in southern England during the early part of the 19th century. . Owen recognized that these reptiles were very different from other known reptiles of the present and the past for three reasons: they were large but distinctly terrestrial, in contrast to the aquatic ichthyosaurs and plesiosaurs that were already known; They had five vertebrae in their hips, whereas most known reptiles have only two; And, instead of spreading out their limbs as in lizards, dinosaurs kept their limbs in a columnar form at the bottom of the body, like elephants and other large mammals.
Originally applied to just a handful of incomplete specimens, the clade Dinosauria now includes more than 800 generic names and at least 1,000 species, with new names each year as the result of scientific explorations around the world. Being added to the roster. However, not all these names are valid taxa. Many of them are based on fragmentary or incomplete material that actually came from two or more different dinosaurs. In addition, bones are sometimes misidentified as dinosaurs when they are not from dinosaurs at all. Nevertheless, dinosaurs are well documented by abundant fossil remains from every continent on Earth, and the number of known dinosaurian taxa is estimated to be 10–25 percent of the true past diversity.
There is a note in the 1820 American Journal of Science and Arts by Nathan Smith that the oldest verified published record of dinosaurs still exists. The described bones were found in 1818 by Solomon Ellsworth, Jr., while he was digging a well at his home in Windsor, Connecticut. At the time, the bones were thought to be human, but much later they were identified as Anchisaurus. Even earlier (1800), large bird-like footprints were observed on sandstone slabs in Massachusetts. Pliny Moody, who discovered these tracks, attributed them to “Noah’s raven”, and Edward Hitchcock of Amherst College, who began collecting them in 1835, regarded them as a giant extinct bird. Tracks are now recognized as having been made by several different types of dinosaurs, and such tracks are still common in the Connecticut River Valley today.
The better-known ones found in southern England in the early 1820s are William Buckland (a pastor) and Gideon Mantle (a physician), who described Megalosaurus and Iguanodon, respectively. In 1824 Buckland published a description of Megalosaurus, the fossil of which mainly consisted of a lower jaw bone with few teeth. The following year Mantle published his “Notice on the Iguanodon, A Newly Discovered Fossil Reptile, in the Sandstones of Tilgate Forest, Sussex” based on several teeth and some leg bones. Both men collected fossils as a business and are credited with the earliest published declarations in England of what would later be identified as dinosaurs. In both cases, his search was so fragmented that a clear image of either animal could not be allowed. In 1834 a partial skeleton was found near Brighton, which matched the mantle fragments of Tilgate Forest. It became known as Maidstone Iguanodon, after the village where it was discovered. Maidstone skeletons provided the first glimpse of what these creatures looked like.
A different type of skeleton was found in Weld, southern England, two years before the Maidstone Iguanodon came to light. It was described and named Hyalosaurus by Mantell in 1832 and later proved to be one of the armored dinosaurs. Other fossil bones began to turn up in Europe: fragments described by two English students, Henry Riley and Samuel Stutchbury, and named as Thecodontosaurus and Paleosaurus, and the first of many skeletons named Plateosaurus by naturalist Hermann von Mayer in 1837. Richard Owen made two Identified additional dinosaurs, though from fragmentary evidence: Cladeiodon, which was based on a single large tooth, and Cetiosaurus, which he named from an incomplete skeleton made of much larger bones. After carefully studying most of these fossil specimens, Owen assumed that all of these bones represented a group of large reptiles that were not unlike any living varieties. In a report to the British Association for the Advancement of Science in 1841, he described these animals, and the term dinosaur was first published in the Proceedings of the Association in 1842.
Basic Dinosaur Facts
Dinosaurs are a group of reptiles that have lived on Earth for about 245 million years. 1842, English naturalist Sir Richard Owen coined the term dinosaur, derived from Greek dinos, meaning “terrifyingly great,” and sauros, meaning “lizard.”Dinosaurs on all seven continents fossils have been found. All nonavian dinosaurs became extinct about 66 million years ago.
Modern birds are a type of dinosaur because they share a common ancestor with non-avian dinosaurs.
Paleontologists are like detectives who investigate the evidence that extinct animals have been left behind. Clues to what dinosaurs were like are found in fossils—the ancient remains of an organism, such as a tooth, bone, or shell—or evidence of animal activity, such as footprints and trackways.
Everything we know about non-avian dinosaurs is based on fossils, including bones, teeth, footprints, tracks, eggs, and skin marks. For centuries, people all over the world have discovered amazing fossil bones and footprints. Early inspired legends and fairy tales abound, as people imagined these bones to be of giants or giant monsters.
Some consider Barnum Brown, who began his career at the American Museum of Natural History in 1897 as one of the greatest dinosaur hunters of the late 19th and early 20th centuries. He began his career at the American Museum of Natural History in 1897. Many of his great discoveries, including the first specimens of Tyrannosaurus rex, are on display in the museum’s Dinosaur Hall.
Age of dinosaurs
The earliest known dinosaurs appeared during the Triassic period (about 250 to 200 million years ago). Dinosaurs evolved into a very diverse group of animals with a huge range of physical characteristics, including modern birds.
Contrary to what many people think, not all dinosaurs lived during the same geologic period. Stegosaurus, for example, lived during the Late Jurassic period, about 150 million years ago. Tyrannosaurus rex lived during the Late Cretaceous period, about 72 million years ago. Stegosaurus was extinct for 66 million years before Tyrannosaurus walked the Earth.
During the Mesozoic Era (a period of more than 180 million years that included the Triassic, Jurassic, and Cretaceous periods), a genus of non-avian dinosaurs evolved into a genus of avian dinosaurs. This avian dinosaur is the first bird and precursor of all birds. Every non-avian dinosaur became extinct 66 million years ago.
Several theories contributed to the mass extinction of non-avian dinosaurs and other species at the end of the Cretaceous period. During this time a giant asteroid or comet certainly collided with the Earth, causing a dramatic change in the Earth’s climate. Some scientists speculate that this impact had disastrous consequences for life on Earth. But other factors, including sea-level changes and massive volcanic activity, may have also played a significant role in this mass extinction.
Dinosaur fossils and fossils
Paleontologists use fossil evidence preserved in ancient rock to find out how long-extinct animals lived and behaved. In most cases, a fossil bone is actually a rock made of minerals, with no trace of the original bone material. The discovery of dinosaur eggs and nests provided evidence of some dinosaur behavior. By comparing the skulls of Protoceratops from different eras (like in the image above), paleontologists can draw conclusions about how some dinosaurs evolved.
Fossil jaws, teeth, and dung provide important clues about what nonavian dinosaurs ate. A series of fossil footprints, called trackways, reveal some intriguing evidence about dinosaur behavior and locomotion.
Until some time ago it was believed that feathers are unique to birds. However, recent discoveries have uncovered evidence for feathered nonavian dinosaurs.
Teeth, footprints and feathers
Most theropod dinosaurs, such as Tyrannosaurus, had sharp teeth, slightly curved back, and serrated. The sharp points pierced the meat, and the serrations helped to cut it by grasping and tearing the muscle fibers. Meat eaters did not cut or grind their food; He swallowed the pieces whole.
The teeth of plant-eating dinosaurs were of various shapes designed for their specialized diet. For example, Triceratops had hundreds of teeth that formed a solid “wall” with sharp ridges. Teeth were used to cut vegetation. Other plant-eaters, such as anatotitans, had broad, flattened teeth that they used to grind tough vegetation. Long-necked dinosaurs, such as Diplodocus, had long pencil-like teeth that they used to rake leaves from branches. These dinosaurs swallowed the leaves whole. They also swallowed small stones, called gastroliths, most likely to grind food into their stomachs, just as modern birds, such as parrots and chickens, do today.
From a personal footprint, scientists can estimate the height of the dinosaurs that built it. A rough estimate of foot length is obtained by multiplying the length of the print by four.
A footprint may also provide clues about the type of dinosaur that made it. A three-legged, sharp-toed print meant that the footprint-maker was probably a theropod—usually a carnivore. A three-toed print with rounded toes probably belonged to an ornithopod dinosaur—a herbivore. And the pairs of unequally sized prints were most likely the work of four-legged, long-necked, long-tailed dinosaurs called sauropods, another group of herbivores.
What are dinosaurs?
Dinosaurs are a diverse group of reptiles that were the dominant terrestrial life form on Earth during the Mesozoic Era, about 245 million years ago. The dinosaurs collapsed at the end of the Cretaceous period, about 66 million years ago.
How did most dinosaurs become extinct?
The decline of the dinosaurs was most likely caused by several different factors. One popular theory is that an asteroid crashed into the Yucatan Peninsula 66 million years ago, ejecting enough terrestrial and asteroid material into the atmosphere that sunlight was probably blocked for several years. This would have had a severe impact on plant life and later led to the death of most dinosaurs.
Did dinosaurs have feathers?
Some species of dinosaurs, such as dromaeosaurs, have fossil records of their feathers. Early wings were not developed for flight; Instead, scientists speculate that dinosaurs evolved feathers for other reasons, such as temperature regulation, camouflage, and balance while running. While most species are often depicted as wingless, some researchers believe that feathers were common on dinosaurs. learn more.
Do dinosaurs exist today?
It is generally accepted that modern birds are descendants of dinosaurs. Evidence for this theory first arose from the fossil record of Archeopteryx and Xiaotingia, two species of theropod dinosaurs that displayed anatomical structures similar to those of birds.
Which is the biggest dinosaur?
Although estimates vary, one of the contenders for the largest dinosaur is Argentinosaurus. Discovered in Argentina in 1987, Argentinosaurus is estimated to be 37 to 40 meters (121 to 131 ft) long and weighs up to 100 metric tons.
When was the first dinosaur fossil discovered?
Dinosaur fossils and tracks have been discovered throughout human history. The first description of dinosaurs as a distinct group of life forms (referred to as “Dinosauria”) was published in 1842 by British paleontologist Richard Owen, who based his findings on fossil fragments of Cladeiodon and Cetiosaurus.
What dinosaurs are still alive today?
Other than birds, however, there is no scientific evidence that any dinosaurs, such as Tyrannosaurus, Velociraptor, Apatosaurus, Stegosaurus, or Triceratops, are still alive. These, and all other non-avian dinosaurs became extinct at least 65 million years ago at the end of the Cretaceous Period.
What was the first dinosaur?
Art by Mark Witton. For the past twenty years, Eoraptor has represented the beginning of the Age of Dinosaurs. This controversial little creature–found in the roughly 231-million-year-old rock of Argentina–has often been cited as the earliest known dinosaur.
How many dinosaurs have been found?
Estimates vary, but in terms of extinct non-avian dinosaurs, about 300 valid genera and roughly 700 valid species have been discovered and named.
Who is the king of dinosaurs?