The living nature of our planet is surprising - both by its diversity and by the characteristics of each individual creature. But the other inhabitants of the planet are exclusively ancient creatures who lived here for millions and hundreds of millions of years, almost without changing at all. Which of the living creatures today can be called the most ancient?

You can list many creatures whose ancestors lived in very old times. Many of them surprise with their appearance.

The first mammals are marsupials

Australia, due to its isolation, has preserved the oldest mammals - marsupials and cloacal. The first category includes koala, kangaroo, and the second - the platypus and echidna. Such creatures flourished in the Mesozoic, and for the first time they appeared 190 million years ago. The evolutionary process has led to the emergence of more complex mammals that could produce fully formed cubs that do not need a bag.

They supplanted their primitive ancestors, who remained only in Australia. The echidna and the platypus carry eggs without being birds. And kangaroos and other marsupials give birth to cubs in an embryonic state, which then grow to the nipples in the bag, thus continuing the development that in other mammals passes in utero.

Ants, and in particular Martialis heureka

Ants appeared quite a long time ago, they lived already about 100 million years ago, using the collective mind, as today. However, the appearance of Martialis heureka differs from most contemporaries, preserving its archaic features as much as possible. He does not even have eyes, but there is a well-developed system of hairs on his body. Each of the hairs is sensitive to vibration, pressure, and other indicators, which allows insects to move confidently and engage in their activities.

Sharks, including avian

Sharks appeared more than 150 million years ago, these fish were and remain successful predators, because their anatomy has changed little. Today, there are no huge megalodons left in the oceans, but there is a fiery shark that can live at a kilometer depth. The creature looks like an eel. Like all other sharks, it has a cartilaginous skeleton, and the teeth remain the only full bones in its body. The anatomy of megalodons almost completely corresponds to the structure of the modern great white shark, only the size of our contemporaries is more modest by 2-3 meters.

Shield

Even more ancient creatures are shields, which are rightly attributed to the ancestors of modern crustaceans living in fresh waters. These creatures populated freshwater reservoirs of Pangea at a time when all the continents were brought together. Creatures are small in size, which are from 2 to 4 mm, and they are also distinguished by their amazing survivability. The laid eggs can remain in the silt for years, waiting for optimal conditions for hatching, adult shields are omnivorous up to cannibalism.

Sturgeon fish

Continuing consideration of freshwater inhabitants, it is necessary to note the antiquity of sturgeon fish species. Their age is more than 200 million years, they have found a wide habitat, which today includes Europe and North America. Of all freshwater fish, they remain the largest. This is one of the oldest branches of bone fish, and today many of its species are on the verge of extinction due to valuable caviar, despite the fact that the law protects ancient and rare creatures.

Crocodiles

Crocodiles - contemporaries of dinosaurs, appeared 250 million years ago. But dinosaurs became extinct, and crocodiles live - they turned out to be more tenacious and adapted to changing environmental conditions.Crocodiles have not changed too much over the past millions of years, they can go into hibernation under adverse conditions, not eat for six months, but if there is food, eat it in tens of kilograms. Giant crocodiles of the past became extinct, but there are three-meter Nile crocodiles that were the embodiment of one of the local ancient gods. Miniature caimans live on different continents. Read our article: the largest species of crocodiles.

Coelacanth fish

Latimeria is an even more ancient creature with an age of about 400 million years. It has an archaic body structure, which can tell about those times when the inhabitants of the oceans have just tried to conquer the land. At some point, this fish was considered irrevocably extinct, but then it was again found in the Indian Ocean.

Coelacanths grow to almost two meters in size, they have developed a system of electrosensory organs that allow to study everything around, and lobed fins have no analogues in the modern world. In the distant past, many fish had just such a structure, and then some of them became breathing, began to develop land, continuing to develop fins in the limbs. So evolution began to bring living beings to new territories, hitherto unknown.

Horseshoe crab

The horseshoe crab could appear earlier than dinosaurs, officially its age is equated to 450 million years. An unusual creature, also called a horseshoe crab, is classified as arachnid, and trilobite is recognized as its relative. The creature grows up to 50-60 cm, has a carapace and protective coloring, a tail with a special device that helps in maneuvering and when searching for food. The appearance of the horseshoe crab is surprising and striking.

Nautilus

Nautilus can be up to 500 million years old, according to archaeological finds. These creatures possess exceptionally beautiful and reliable shells, which, obviously, allowed them to survive to this day. Nautilus eat, helping themselves with numerous tentacles, which also help to cope with enemies.

Jellyfish

Another ancient creature living today is jellyfish. They are built very simply, do not have a brain, the nervous system is diffuse, but can be poisonous. Their age is estimated at 550 million years. These jelly-like creatures have sensory organs and the digestive system, but are 90 percent water.

Sponges

Even earlier, sponges appeared on Earth, whose age is estimated at 580 million years. These creatures are so primitive that they resemble more plants, they have no organs, as well as parts of the body, all the cells that make up this structure are of the same type. These creatures live in fresh and sea water, today their diversity is estimated at 8 thousand species.

Cyanobacteria

The most ancient inhabitants of the planet should be considered cyanobacteria - this is the conclusion scientists have come to. They exist on Earth for approximately 3.5 billion years, remaining the oldest inhabitants. The bacterium is able to release oxygen in the process of photosynthesis, it is a byproduct of life. It was probably cyanobacteria that saturated the planet’s atmosphere with oxygen, preparing it for the existence of all subsequent inhabitants who needed this gas for respiration. Without them, all those amazing creatures that ruled land and seas at different times would not have arisen. There would be no people either.

Thus, there are many ancient creatures that have survived from past eras on the planet. Each of them is worthy of study, because they were able to survive and survive the era only thanks to their perfection.