< h1 class = "pgc-h-arrow-right" > fish ashore, a very wondrous point in the slow evolution of an ancient creature. </h1>
It's hard to imagine how fish could have climbed from the water to shore and then evolved into reptiles. This process is a long one, and although there are various fossils that prove that fish did leave the water step by step, fossils are always fossils, and no one knows or has seen these 65 million-year-old species.
Until one day in 1938, this happened...
Today Xiaobian will take you to know this kind of living fossil fish that suddenly appeared in front of human eyes and was once thought to have been extinct 65 million years ago - coelacanth fish.
Total fin fish – fish that are not content with water
There is no doubt that coelacanths are living fossils. By any measure of the way you look at it, this fish doesn't look like any modern fish.
It belongs to the once-total finned fish order, a type of fish that is considered an iconic species that landed long before fish landed.
Coelacanth structure
In the late Devonian period, as the earliest type of terrestrial vertebrate, the total fin fish began their long-winded landing process. Their fins have evolved into powerful fleshy even fins that help them crawl on land, and they have primitive lung structures that allow them to breathe on land for long periods of time.
Long gone landing pioneers
The coelacanth is called coelacanth because of its hollow spine. From the fossil record, it is believed that this fish first appeared in the Devonian Period 350 million years ago, and became extinct in the Cretaceous Period.
It has been a frequent visitor to the late Permian to the Cretaceous strata, and it can be seen in most strata of the world. In the formations after the Cretaceous Period, scientists can no longer find the figure of these landing pioneers. As a result, this fish has long been thought to have been completely extinct at the end of the Cretaceous period.
Five mass extinctions
Coelacanth is one of the typical total fin fish that began to make landfall in the Permian. It can crawl on land and breathe in the air, although this is only short-lived, and it cannot live on land for a long time, but this is undoubtedly of great significance for the evolution of terrestrial vertebrates.
Fossil cavity spinosaur
Before the recontroduction of coelacanths, many biologists were convinced that the fish was one of the origins of early amphibians. at
Testing of his DNA after the rediscovery also proved that coelacanths are more closely related to amphibians and tetrapods than fish, which almost confirms the ancient judgment that coelacanths are amphibian ancestors.
So what is the thing that makes this fish, which has long been equated with fossils, reappear in the world? Let the editor tell you about it:
The story of the discovery of the coelacanth
In 1938, it was a Christmas day, and Maroli Courtney-Ratimo, a museum worker in South Africa, did as she usually did, patrolling among the fish caught by local fishermen to see if new species were emerging. At this moment, she was caught by a strange-looking fish, about two meters long, with scales spreading throughout the body like armor, and four thick limbs like terrestrial animals on the abdomen and chest.
Coelacanth with the discoverer Mary
She immediately pulled out her notepad, drew a picture of the fish, and quickly returned to the museum to find information about the fish. Unfortunately, she went through all the materials and couldn't find any record of this fish. So she sent a letter to Professor Smith, a famous ichthyologist in South Africa, and attached a sketch she had drawn to ask the professor for advice.
Illustration of a hand drawing of a coelacanth
Smith was shocked to see the letter, which looked a lot like a long-extinct coelacanth. He immediately set off for Ratimo's seat. Unfortunately, when he arrived, the fish, suspected of being a coelacanth, had only left the bones left.
Coelacanth
Through the analysis of fish bones, this fish is indeed a coelacanth fish 65 million years ago. This conclusion instantly detonated the biological community, and biologists set their sights on the fish.
Is there any such fish? Can you find more? Scientists have countless problems to solve for coelacanth, but with the outbreak of World War II, such matters can only be shelved.
Peak loop turn
During the course of world war II, Professor Smith was obsessed with the living fossil species of coelacanth. After the end of World War II, he distributed leaflets everywhere and traveled to the Indian Ocean coast and even the Pacific coast to find the whereabouts of this species, but to no avail. The coelacanth fish seemed to have never existed, without a trace.
But the fishbone in his hand always reminded Professor Smith that the coelacanth must still exist, and it cannot be just a flash in the pan.
Finally, one day in 1952, a telegram from afar was placed in front of him: "We have caught a fish that resembles a coelacanth, and we look forward to your arrival." "
Professor Smith poses with coelacanth
The telegram was from fishermen in the Comoros. After receiving the telegram, the professor was so surprised that he rushed to the South African government for help, hoping to arrive in the shortest possible time.
The South African government was also very cooperative, and Professor Smith rushed to the scene in a military plane and saw this species reappear in the long river of history.
All efforts have not been in vain.
Why did the coelacanth live to this day
In fact, modern coelacanths are not exactly the same as ancient coelacanths. Although almost all of the structure is exactly the same as that of the ancient coelacanth, it is much larger than its ancient ancestors.
Scientists speculate that this is also one of the evolutions brought about by a long time.
Coelacanths have strong pectoral fins
As for why the species of coelacanth survived to modern times, scientists speculate this way: Ancient coelacanths generally evolved structures that can land, and have also tried to land. However, after landing on land, some of them returned to the sea again for various reasons.
Divers and coelacanths
This part of the return to the sea, because of the evolution of strong skeletal scales and teeth and other nerve equipment, modern coelacanth 1.5 meters to 2 meters in size in the Indian Ocean almost no natural enemies, so there are few opponents in the sea. In addition, it is a carnivorous fish itself, and for the reason that it is at the top of the ecological chain, it has been surviving in the deep sea of the Indian Ocean, forming a living fossil species of modern coelacanth.
brief summary
The discovery of the modern coelacanth is a landmark, it provides key information for the evolution of Permian fish to a certain extent, and its preciousness as a real "living fossil" is self-evident.
In 1982, the Government of the Comoros gave china a specimen of a soaked Ratimi fish, which is now preserved in the vertebrate exhibition hall on the first floor of the Paleozoological Museum of China for visitors to visit.
Specimens donated to our country
Under the wheel of time, every moment there are species that cannot withstand the pressure of nature and go extinct, such natural selection is the eternal melody of nature. The coelacanth has been able to survive in its original form, and one has to sigh at its luck and evolutionary success.
Every species is full of wonders, and nature's ingenuity sometimes amazes us again and again.
But this is not surprising, in the future, there will be more magical creatures waiting for us to discover and explore!