People found giant bones already in ancient times. Until the 19th century, they were considered the remains of ancient giants or magic dragons. Today, every child knows that huge dinosaurs roamed our planet millions of years ago. They could have a height of up to 12 meters and weight up to 100 kg. But when did the first dinosaurs appear and why did they suddenly disappear, leaving behind many mysteries?
Exploring fossils
It is known that giant lizards populated all continents of the Earth, including Antarctica. It is not surprising that their petrified remains were discovered by people throughout their existence. In this regard, it is impossible to name the first dinosaur found.
The Englishman W. Buckland first began collecting bones for scientific study at the end of the 18th century. The professor of geology could not understand to whom they belong. The French naturalist J. Cuvier in 1818 guessed that these were the remains of huge lizards. In 1824, a report was presented in London on the discovery of antediluvian animals called megalosaurs.
In 1825, the doctor Mantel examined the teeth of an unknown beast, which had a length of 4-5 cm. They looked like the teeth of an iguana, so the animal was called the iguana. In 1837, Professor G. Meyer found the bones of a new dinosaur in Germany and named him the plateosaurus (lowland lizard). Only in 1847, London professor R. Owen proved that all finds belong to the same species of reptiles. The group was called dinosaurs, or "terrible lizards."
Characteristic signs
Before talking about the first dinosaurs, we will deal with the distinguishing features of this amazing group of animals. All of them are strikingly different from each other. Some lizards were about the size of a chicken, while others reached the size of a whale. Some ate grass, others led a predatory lifestyle. Someone slowly moved on four legs, someone quickly ran on two limbs.
However, common properties exist:
- All dinosaurs led a terrestrial lifestyle.
- Their limbs were located below the torso, and not on the sides, like other reptiles. The legs were straight. This made the animals very mobile.
- On the skull behind the eye sockets there were two temporal cavities (the other reptiles had one). Due to this, dinosaurs acquired a powerful mobile jaw and keen hearing.
Lifetime
The era of the dinosaurs is considered to be the Mesozoic era. It is divided into three periods: the Triassic (252-201 million years ago), the Jurassic (201-145 million years ago) and the Cretaceous (145-66 million years ago). The first dinosaurs on Earth arose 230 million years ago. At that time, there was only one giant mainland, Pangea, with a hot and dry climate.
In the Jurassic period, the continents moved apart, and seas formed between them. The climate became humid, the deserts were replaced by tropical forests. In such favorable conditions, dinosaurs took a leading position and reached gigantic proportions. But their true heyday came in the Cretaceous period.
The history of the species broke off suddenly. In breeds of 70 million years old, there are many bones and teeth of dinosaurs. However, after 5-6 million years, according to the assurances of paleontologists, huge lizards have completely died out.
Nearest ancestors
But back to the very beginning. Life arose in water. 300 million years ago, the first vertebrate reptiles climbed ashore and began to lay eggs on land. At first they were small (about the size of a lizard), but over time, large predators the size of a crocodile (tecodonts) appeared. Some of them (in particular, birdwatching) were able to run on their hind legs.
The ancestors of the first dinosaurs became archosaurs, in which the arrangement of limbs changed. They did not crawl on widely spaced paws, but moved on straight limbs. A striking example is the lagoon, resembling a rabbit in its size and structure of its hind legs. The front beast could capture the insects that it fed on. The tail at the lagoon was long. Most likely, a stavricosaurus descended from it, the remains of which are 228 million years old.
Very first dinosaur
The first lizards were predators and belonged to the group of theropods (in translation - "furry"). They ran on two legs, had clawed toes on their front legs, and could collect food from them. The earliest dinosaurs found are:
- Eoraptor. This is the oldest species found in Argentina (from 228 to 235 million years ago). The length of the animal is not more than a meter. It can be compared to a dog in size. Estimated weight - 10 kg.
- Stavricosaurus. He had a length of just over 2 m, a height of about 80 cm. The weight of the animal reached 30 kg. The lizard was very fast.
- Herrerazavr. This is the most primitive dinosaur about 4 m long. Its weight ranged from 200 to 250 kg. The predator hunted lizards, small reptiles, as evidenced by sharp bent teeth.
The appearance of herbivorous dinosaurs
Following predators, lizards appeared, eating plant food. Most of them were quite large. The first vegetarian dinosaur was a plateauosaurus with a long neck and a body resembling a pear. The length of the animal ranged from 6 to 12 m. Weight reached 4 tons.
A giant walked on four legs. A powerful pelvis and a muscular tail allowed the plateauosaur to stand on its hind legs, as a modern kangaroo, and reach the crowns of ferns 5 m high.
Lifestyle
The period of the first dinosaurs ended with their complete victory over other species inhabiting the planet. Such bizarre creatures had never lived on Earth before. A variety of shapes and sizes still amaze scientists.
All dinosaurs can be divided into two groups: predators and herbivores. The first ran on two powerful legs and had a flexible tail. Most of the predators reached a length of 2 to 4 meters. But there were giants like a tyrannosaurus and a giantosaurus up to 15 m long and weighing up to 8 tons. They hunted the largest herbivorous dinosaurs.
The latter preferred to move in herds in order to be able to protect the cubs. Many of them had horns, bone growths or tail spikes to help withstand the battle. Herbivorous dinosaurs had different sizes, which allowed them to eat leaves from different tiers. The largest are brachiosaurus and diplodocus up to 40 m long and weighing more than 100 tons. They lived on land and were extremely slow.
Dinosaur cubs hatch from eggs. Parents fed them in nests, as birds still do. Many scientists believe that the largest of the dinosaurs were viviparous. After all, the largest of the eggs found has dimensions of only 30 cm. Yes, and not all species could remain in one place for a long time to protect eggs and cubs.
Sudden Doom: Hypotheses
No one has yet given an exact answer to the question why all the dinosaurs disappeared from the planet 65 million years ago. After all, crocodiles, snakes, turtles, lizards, mammals and birds that lived at the same time still exist. The most plausible version is the change in the familiar ecosystem.
She could be called:
- The fall of a large asteroid, which led to the activation of volcanoes and large emissions of dust. The sun's rays ceased to enter the Earth’s atmosphere, many plants died, a cold snap came.
- By evolution, during which gymnosperms disappeared, which were mainly eaten by herbivorous dinosaurs. They were replaced by flowering species, but the giants were not able to adapt to a new type of food. After a sharp reduction in their numbers, predatory dinosaurs began to die out .
- The movement of lithospheric plates, which led to a change in currents in the ocean and a sharp cooling.
- A flash of a supernova, due to which hard cosmic irradiation hit the planet.
It is unlikely that we will find out how it was in reality. In any case, the first dinosaurs laid the foundation for a glorious era that lasted 150 million years. In memory of her we left huge bones of extinct giants and many mysteries that excite the imagination.