During the Devonian period, which fish were kings?

With the end of the Silurian period, the evolutionary history of the earth entered the second half of the Paleozoic era, the Quaternary-Devonian. Just as the Ordovician continued the Cambrian explosion, the Devonian also inherited the vitality of the Silurian period, and the variety and number of organisms reached an unprecedented scale. Lush ferns and rising insects and amphibians have grown to unprecedented sizes.

In particular, vertebrates, represented by fish, entered a period of rapid development, so the Devonian period is often called the "age of fishes".

In fact, the age of "fish in the north" is also the result of paleogeographic evolution. Under the influence of the Caledonian movement in the early Paleozoic Era, the Earth's Hercynian movement began in the Devonian period, and many areas rose to the surface of the sea to become land, covering 85% of the Earth's seawater, including the vast Paleo-Pacific Ocean in the Northern Hemisphere. Compared to the Early Paleozoic, the paleogeographic features have changed a lot:

The largest and most complete ancient land, Gondwana, is distributed around the Antarctic region; The two ancient lands of Lauren and Boro formed the unified continent of Europe and the Americas, gradually approaching the ancient land of Gondwana; In the Late Devonian, the two ancient continents began to gradually converge near the equator, laying the foundation for the formation of the Pangea supercontinent in the future.

Just as the 6-metre-long straight-shelled nautilus, which represents the evolution of the Ordovician, gave way to the Ordovician new generation of marine giant crabs and horseshoe crabs, the Devonian period also underwent a great shift in sovereignty: vertebrates with double jaws finally emerged as the brightest stars. The dominance of arthropods and mollusks on the planet is a thing of the past.

Vertebrates firmly occupy the throne of the largest, strongest, and most ferocious creatures on the planet.

In the Devonian rivers and seas, the vertebrates were mainly fish, such as jawless bony fish, soft-shelled turtles, scale fishes, and miscellaneous fish (collectively referred to as "soft-shelled turtles"); There are four branches of jawfish: shieldfish (fish in dungeons), spiny fish, cartilaginous fish (sharks), and bony fish. You're singing too loudly.

Among them, jawless species flourished in the early Devonian period, and with their sturdy armor, they were also able to occupy a place in the waters where Silurian flounders were rampant. But in the middle of the Devonian, when the fierce and strong jawless fish appeared, the powerful jaws and sharp teeth not only completely shattered the rule of the horseshoe crab, but also killed the warm and heavy jawless relatives. Only a few specialized jawless animals have survived and become the ancestors of modern round-mouthed animals.

Dun's fish. Huge in size about the size of a bull, the blood basin is terrifying.

Shield fishes, one of the largest predatory fish in the Devonian period, can reach up to 9 meters in length, and have not yet evolved real teeth. Dunkle's fish, which emerged during the Late Devonian period, is considered to be the largest predator in the oceans at that time. Arthrophular fish with heavy armor on its body.

The Devonian period, sometimes referred to as the "Age of Fishes", evolved during the late Silurian period or the beginning of the Devonian, so in the early Devonian period, most fish had armor-like bone plates on their bodies, and jawless fishes were also common fish species at that time.

In addition to the dungeon's fish as described in **, there are many representative fish. By the end of the Devonian, the fishes differentiated into the current classes and subclasses - jawless fishes, cartilaginous fishes, radial-finned fishes, leaf-finned fishes, and bony fishes, which flourished in the middle Devonian. In addition, two other species of fish appeared in the late Ordovician and diversified during the Silurian period, and flourished in the Devonian period. In fact, the shield fish was one of them, and it was the dominant fish in the Devonian, and by the end of the early Devonian period, the species and number of the shield fish replaced the jawless fish.

The other is the echinoderm, which also flourished during the Devonian period, with jaws and bones, but also some characteristics of cartilaginous fishes. However, the shield fish became extinct at the end of the Devonian, and the echinoderm also declined in growth at the same time, until it became extinct in the Permian.

Drepanaspis gemuendenensis, a jawless fish that appeared in the early Devonian period;

The head, trunk and pectoral fins of the genus Bothriolepis are covered with bony armor composed of multiple nail pieces, and the trunk is particularly well developed.

Ancient sharks belonging to cartilaginous fishes , the arcuate weeping shark Orthacanthus Arcuatus , with long spines that elongate from behind the skull and very long tail fins like eels;

the Humberg stinger shark Xenacanthus humbergensis, with its banded dorsal fin and distinctive backbone, hence its name;

The jaw joints of the Paterson slit shark Cladoselache pattersoni were more fragile than those of today's sharks, but had stronger jaw muscles.

belonging to the jawless fishes, the pinned turtle pteraspis rostrata, the most typical of the armoured fish family, was abundant in the late Silurian and early Devonian periods;

Doryaspis nathorsti has serrated lateral edges of gill plates and false snout.

belonging to bony fishes, serrated dipterus serratus ;

Short barramundi scaumenacia curta.

The Devonian period is the fourth of the six Paleozoic periods, between the post-Silurian and pre-Carboniferous periods. The Devonian period began 100 million years ago and lasted until 100 million years ago. The Devonian is divided by geological time, which can be summarized into the Early Devonian, Middle Devonian and Late Devonian.

Devonian vertebrates experienced an almost explosive developmentBoth freshwater and marine fish are abundant, and these fish include primitive jawless armoured fishes; Shield-skinned fish with jaws and armor; and real sharks. There is also a shark-like arthrophoid with a body of up to 9 meters and a heavy armor attached to the jaw. The new type is the lungfish, a primitive type that has both gills and developed lungs as auxiliary respiratory organs, some of which are still alive today, forming an important link between fish that breathe with gills and amphibians who breathe air with lungs.

Not only did it transform the pouch into a primitive lung, but some of these fish evolved into pairs of broad-finned flippers, allowing them to live on the surface for a short period of time, while having limited locomotion on land.

Given the unprecedented evolution of vertebrates, the Devonian period was once known as the Age of Fishes. The most important is to show the appearance of tetrapods (quadruped vertebrates), primitive reptiles that evolved from the totalfins.

Head turtle, pectoral shark, dunkle fish, lungfish.

The Devonian period was a period of rapid development of vertebrates, fish flourished, and many fish appeared. So the Devonian period is called the age of fish, and above all shows the appearance of primitive reptiles, tetrapods and quadruped invertebrates, which evolved from the general fin.

Because of the microbial and nutrient energy of the rivers during the Devonian period, the microorganisms and nutrients in the rivers benefited the fish well, so that the fish could grow rapidly.

The Devonian period is a period of rapid development of vertebrates, fish are quite prosperous, various types of fish have appeared, so the Devonian period is called the age of fish, the most important is to show the emergence of primitive reptiles quadruped quadruped invertebrates that evolved from the total fins.

The Devonian, often referred to as the age of fishes, began 100 million years ago, after important crustal movements, when the distribution of the world's land and sea changed dramatically, and the slow-growing simple plants of the Silurian on land gradually gave way to more viable species that left the water environment, and by the end of the Devonian, the first forests had been formed.

The Devonian period refers to the 60 million years between 100 million years ago and 100 million years ago. From the Devonian period, the land area of the Earth expanded, thanks to active crustal movements. It was also from this time that the land was no longer a barren land lacking life, and with the expansion of the land area, plants adapted to the land environment began to grow in large numbers, as well as many huge ancient insects and amphibians that had just come ashore.

However, this is only the beginning of land life, and it is the marine life, especially fish, that flourishes the most. In the Devonian period, fish were all over the ocean, and they were the masters of the ocean at that time, so the Devonian period is also called the "Age of Fishes".

Devonian continental map.

The most abundant fish in the Devonian period was the shield fish, and the dominant marine fish at that time was the Dunkle fish, which belonged to the shield fish. The Dunkle had a strong bite force and could bite a shark in half in one bite, so it was rightfully at the top of the food chain at the time.

The ferocious Dunkle was the overlord of the seas of the Devonian period.

The second mass extinction event in the history of the earth occurred in the late Devonian, resulting in the extinction of 75% of all living things at that time, and the marine life was the hardest hit area.

Imagination of the early Devonian mass extinction.

With the end of the second mass extinction, the age of fish also ended, and was replaced by the age of amphibians, in which amphibians flourished.

The above content refers to Milley's children's book "A Brief History of Life".

Because the number and variety of ichthyomorphs increased during the period of rapid development of vertebrates in the Devonal Period, the modern fish, the bony fish, began to develop. The Devonian period is often referred to as the "Age of Fishes". Hope to adopt.