Scientists have calculated that vertebrates have inhabited our planet for about 500 million years, 200 million of which are dominated by ancient lizards called dinosaurs. At one time, the ancient reptiles were the crowning creation of mother nature, and their offshoot - dinosaurs - generally personified the pinnacle of development of all reptiles that have ever inhabited our planet. All kinds of dinosaurs, as well as their way of life, changed each other in different eras, and nature made new adjustments to their lives.
Who are paleontologists?
Before we find out what types of dinosaurs lived on our planet in different eras, we need to understand how it all began. The study of life that originated in distant epochs is the science of paleontology. Its name comes from three Greek words: "paleos" - ancient, "ontos" - being, "logos" - word. People who practice this science are calledpaleontologists. Their work is somewhat reminiscent of the work of detectives: paleontologists need to restore a whole picture of bygone eras from scattered fragments and remains. Their intuition, combined with logic and imagination, plays a huge role in this.
Even the smallest facts need careful research. Paleontologists collect them bit by bit. This is a rather painstaking and exhausting work, because many events of the past have irretrievably gone into oblivion, without even leaving a single trace in the rocks. It is thanks to the work of these people that we can learn about what kind of animals once inhabited the planet Earth, what types of dinosaurs existed, how they looked, how they lived, who they hunted, how they escaped from certain dangers. Paleontologists were able to bit by bit recreate a picture of the world around the great era of dinosaurs.
How was the age of dinosaurs formed?
Of course, all kinds of dinosaurs and the varieties that branched off from them during the great era of reptiles could not have become so numerous and widespread if our planet had not developed and formed accordingly. The era of dinosaurs is usually divided into several periods. Let's look at each one briefly.
- Archaeus. This is the very first, the earliest period. This is the starting point from which the era of reptiles originates. At that time, life was just beginning to emerge on Earth, the evolution of unicellular organisms was taking place.
- Proterozoic. During this period, multicellular organisms began to appear on the planet.animals and plants.
- Cambrian. In the Cambrian period, life on Earth began to develop actively, algae and aquatic invertebrates appeared.
- Ordovician. It was this time that was marked by the appearance on the planet of the first vertebrate creatures.
- Silur. In the Silurian period, invertebrates and some plant species move from water to land.
- Devon. This time is characterized by the appearance of gymnosperms, as well as animals such as amphibians, arachnids (spiders, ticks), insects.
- Carbon. It is from here that the era of ancient reptiles originates. The reptiles that appeared during this period were divided into three branches: anapsid, synapsid, diapsid. At the same time, the first coniferous plants and flying insects began to appear on the planet.
- Perm. The Permian period is marked by the appearance of the first beetles, bedbugs, hymenoptera, the first small lizards and the first archosaurs.
- Triassic. Paleontologists have found that it was at this time that the first flies began to inhabit our planet, while the last ancient amphibians - stegocephals - began to die out. Representatives of the anapsid class also died out. In the Triassic period, the first crocodiles, turtles, flying lizards, mammals and, of course, dinosaurs appeared.
- Yura. The Jurassic period is a kind of culmination of the dinosaur era. It was at this time that angiosperms appeared on Earth, butterflies began to fly, some modern amphibians (the same green frogs) were born, ancient birds (Archeopteryx) and, of course, new types of dinosaurs arose. In the Jurassic period,the last members of the synapsid class to die out.
- Chalk. Angiosperms finally conquered the land. Modern species of ants and blood-sucking insects appeared. In addition, the Cretaceous period is the end of the great era of reptiles: it was at this time that the complete extinction of dinosaurs, marine reptiles, and pterosaurs occurred. It was the Cretaceous period that was marked by the appearance of some modern animals: new smart and beautiful animals began to conquer our planet - placental mammals, marsupials and birds.
Anapsid subclass
Before the planet Earth began to be populated by different types of dinosaurs, it took many years to form the so-called family tree of terrible lizards. The most ancient and most primitive group is considered to be the Anapsid subclass. We note right away that not a single representative of this group has survived in one form or another to this day. The last anapsids became extinct about 200 million years ago. It happened in the Triassic period.
Subclass synapsid
From the very root of the anapsids, the second evolutionary branch of future dinosaurs, synapsids, separated. The ancestors of mammals belonged to this ancient class. But they were also destined to sink into oblivion. So, unfortunately, without seeing the heyday of their descendants - modern mammals, to which we belong - people. It happened in the Jurassic period.
Diapsid subclass
Significantly later, the synapsids separated from the base of the ancient trunk a new branch - the diapsids. Its uniqueness lies in the fact thatit was the diapsid subclass that split into two more branches - into archosaurs and lepidosaurs. Lepidosaurs are a group of animals that live on Earth today: tuatara (ancient lizards), snakes, turtles. But not all lepidosaurs were able to survive to our era, among them there are known extinct forms, such as plesiosaurs - marine predators with long necks. According to legend, one such plesiosaur named Nessie still lives in the Scottish Loch Ness, but that's another story.
The branch of archosaurs was represented by crocodiles and other ancient reptiles, among them all kinds of flying dinosaurs, and land lizards. Archosaurs are the most important lizards of all times and eras, one of the most diverse and amazing reptiles, the most advanced reptiles of that time. Fortunately, all dinosaurs died out before they survived to this day, but at present, several species of ancient crocodiles that have survived from those very times live on planet Earth! What were these legendary lizards? We bring to your attention the most striking types of dinosaurs and their description.
Peaceful Diplodocus
This is a representative of a group of so-called sauropods. According to paleontologists, these dinosaurs could reach a length of up to 58 meters and weigh 113 tons. However, more and more modern scientists are inclined to believe that diplodocus did not exceed a length of 27 meters and a weight of 20 tons. The first fossils of this peaceful pangolin were found by paleontologists in 1877 in the mountains of Colorado, USA.
Types of dinosaurs of thisgroups lived in the late Jurassic period on the territory of modern North America about 150 million years ago. Paleontologists consider diplodocus to be one of the most easily identifiable dinosaurs. Moreover, this species is the largest of all dinosaurs known from complete skeletons found. Diplodocus were herbivores, and their huge size was a deterrent to the predatory lizards of those times - ceratosaurs and allosaurs.
Allosaurus - Diplodocus Thunderstorm
In the framework of this article, we will not be able to consider all types of dinosaurs with names, so we will only turn to the most prominent and famous representatives of these legendary giants. One of them is the Allosaurus. This is a representative of the genus of carnivorous dinosaurs from the group of theropods. Like diplodocus, allosaurs existed in the Jurassic period about 155 million years ago.
These creatures walked on their hind legs and had very small forelimbs. On average, these lizards reached a length of 9 meters and a height of 4 meters. Allosaurs were considered large bipedal predators of the time. The remains of these insidious creatures were found on the territory of modern Southern Europe, East Africa and North America.
Ichthyosaurs are legendary fish lizards
Represent an extinct order of large marine reptiles, reaching a length of 20 meters. Outwardly, these lizards resembled modern fish and dolphins. Their distinguishing feature was large eyes, protected by a bone ring. In general, at a short distance, ichthyosaurs could well be mistaken for fish ordolphins.
The origin of these creatures is still in question. Some paleontologists believe that they come from diapsids. This version is supported only by conjectures: apparently, the escape of ichthyosaurs somehow branched off from the main diapsid stem even before this subclass split into archosaurs and lepidosaurs. However, the ancestors of these fish lizards are still not known. Ichthyosaurs died out about 90 million years ago.
Dinosaurs take to the skies
At the end of the Triassic period, the first flying species of dinosaurs appeared on the planet, which appeared unexpectedly in the fossil record. Curiously, they were already fully formed. Their direct ancestors, from which they evolved all this time, are unknown.
All Triassic pterosaurs belong to the Rhamphorhynchus group: these creatures had huge heads, toothy mouths, long and narrow wings, a long and thin tail. The size of these "leather birds" varied. Pterosaurs, as they were called, were mostly the size of both gulls and hawks. Of course, among them were 5-meter giants. Pterosaurs became extinct about 65 million years ago.
Tyrannosaurs are the most famous dinosaur species
The list of ancient lizards would be incomplete if we did not mention the most majestic dinosaur of all times and eras - the Tyrannosaurus Rex. This insidious and dangerous creature fully justifies its name. This creature represents a genus of carnivorous dinosaurs from the group of coelurosaurs andsuborder theropods. It includes a single species - a tyrannosaurus rex (from the Latin language "rex" is a king). Tyrannosaurs, like allosaurs, were bipedal predators with massive skulls and sharp teeth. The limbs of a Tyrannosaurus rex were a complete physiological contradiction: massive hind legs and tiny hook-shaped forelegs.
Tyrannosaurus rex is the largest species within its own family, as well as one of the largest terrestrial predatory lizards in the entire history of our planet. The remains of this animal were found in the west of modern North America. According to scientists, they lived about 65 million years ago, that is, it was in their century that the death of the entire dynasty of ancient lizards occurred. It was the tyrannosaurs that crowned the entire great era of dinosaurs, which ended during the Cretaceous period.
Feathered heritage
For many people it is no secret that birds are direct descendants of dinosaurs. Paleontologists saw much in common in the external and internal structure of birds and dinosaurs. It should be remembered that birds are descendants of land lizards - dinosaurs, and not flying lizards - pterosaurs! Currently, two subclasses of ancient reptiles are "hanging in the air" because their ancestors and exact origins have not been established by paleontologists. The first subclass is ichthyosaurs, and the second is turtles. If we have already de alt with ichthyosaurs above, then nothing is clear at all with turtles!
Turtles are amphibians?
Therefore, it is clear that, considering such a topic as"Species of dinosaurs", it is impossible not to mention these animals. The origin of the turtle subclass is still shrouded in mystery. True, some zoologists still believe that they originated from anapsids. However, they are opposed by other pundits who are sure that turtles are the descendants of some ancient amphibians. And they do not depend on other reptiles at all. If this theory is confirmed, then there will be a big breakthrough in the science of zoology: it may happen that turtles will not have the slightest relation to reptiles at all, because then they will become … amphibians!
