One of the most important zoological discoveries of the 20th century was the discovery of coelacanths, which gives us a glimpse into the dignity of the ancestors of human fish.
The strange fish that was inadvertently caught by others is actually a real living "dinosaur".
In December 1938, a tugboat caught a strange-looking fish while fishing along the shallow waters of South Africa, and because of its large size and strange appearance, it immediately attracted the attention of the fishermen, who gathered around to watch. The fish was so large, about two meters long, and had a vicious face, and the fishermen had never seen such a strange fish before. They still don't know how important the fish they inadvertently caught in the net is: it's a real living "dinosaur."
Upon returning to port, the fishermen gave the strange fish to the East London Museum. The fish had been dead for a long time when it was delivered to the museum. The museum's director, Ms. Courtney Latimer, faced a very difficult problem: existing storage equipment could not preserve such a large specimen. So she wrote a letter to Smith, a famous ichthyologist in South Africa, asking him to come and see the strange fish as soon as possible. However, before Dr. Smith arrived, the fish had rotted so badly that Miss Latimer had to peel off the skin, throw it away, and save the skull and skin for specimens.
When Dr. Smith arrived to see the fishskin specimen, he immediately realized that what was before him was the greatest zoological discovery of the century: a fish thought to have gone extinct 60 million years ago, belonging to a very old fish suborder, the direct ancestor of all amphibians, reptiles, birds and mammals.
In the eyes of many people, the fish are the same and nothing special, so this unusual discovery did not attract the public's special attention. But in the eyes of biologists, the new discovery is epoch-making: it is a living coelacanth that, until then, was thought to have long since become extinct like dinosaurs, but they survived.
It is the common ancestor of reptiles, birds and mammals, including us humans.
What kind of fish is the coelacanth? This is a completely different fish from the common polygonal fish and the sharks we know as well. It belongs to a separate taxon of a suborder of total finfish, also known as limb-like finfish. In short, the total fin fish looks distinctive, with a raised forehead, two dorsal fins (most fish have only one dorsal fin), a pair of limb-like fins, and the skeletal structure inside shows the same structural position and relationship with the legs and feet of terrestrial vertebrates, which are very different from the fin structure of ordinary fish. Another special feature of the coelacanth is that the tail has a long axis, or its vertebrae extend all the way to the tip of the tail. The gill lid of the coelacanth is degenerate, the scales are large and thick, and there are many wrinkles on the surface, covering a layer of enamel.
Total fin fish can not only breathe air, but also walk with their fins as feet, which is important evidence of the evolution of fish to amphibians. During the Devonian period, 300 million years ago, the ancestors of coelacanths climbed onto land with their strong fins. After a period of struggle, one of them became more and more adapted to life on land, eventually evolving into a true tetrapod; while the other, frustrated on land, had to return to the sea and find a quiet corner in the ocean, saying goodbye to the land once and for all.
Unfortunately, the body part of the fish caught by the fishermen has not been preserved, so there are still many unsolved mysteries about the internal structure of the coelacanth, especially the lung-like air maw, and various speculations about the air maw (a calcified or partially hardened air maw found on the coelacanth fossil) are not solved until the second coelacanth is captured.
The discovery of live coelacanths overturns all man-made speculations. In the past, it was thought that coelacanths became extinct in the Mesozoic Era, when dinosaurs still ruled the landing grounds. However, even so, they have lived far longer than the dinosaurs, because the ancestors of the coelacanth can be traced back to the Devonian period 300 million years ago, when dinosaurs had not yet appeared, not only dinosaurs, but also any terrestrial vertebrates had not yet been born. The limb-like fins of the Devonian total-fin fish are the prototype of the limbs of later vertebrates, and it is not only the direct ancestor of its surviving descendants of the echinospidocene that have hardly changed, but also the direct ancestors of the first amphibians who bravely stepped out of the waters and landed on land to begin a new life. They are also the ancestors of reptiles, birds and mammals, including us humans. By observing the extant coelacanth, we can see the general appearance of the ancient total fin fish 300 million years ago, which can also obtain a general image of our human fish ancestors.
Before the discovery of living coelacanths, all coelacanths, as well as all ancient total fin fish, were identified by fossils. Scientists' reconstructed images of the fish are also based on fossil remains preserved in rocks 60 million years ago. Now a "living fossil" fish has swum into the field of scientists, and they can study it to compare their previous recovery accuracy of the fish. To the scientists' delight, the fish they saw matched their previous imagination. That is, the restored images made from the fossils are now proven correct. In particular, the re-sleeping pottery of the two fossil coelacanths shows how similar they are to modern coelacanths, and are close relatives of the extant coelacanths.
Now let's go back to this story of discovery. When Dr Smith saw this great discovery in front of him, he immediately wrote a letter and sent it to London. However, scientists there don't pay enough attention, because old-fashioned scientists are sometimes skeptics, especially when they are confronted with something that shocks the world. Dr Smith then gave a brief description of the fish and gave it a new name, Latimeria chalumnae (in honor of Miss Latimer, who first discovered that it was a new species), and then he sent the caption to London along with a picture of the fish. Things finally took a turn.
Scientists held a meeting at the Burlington Pavilion, which was attended by many world-renowned fish experts. After carefully studying the pictures and descriptions, the scientists finally confirmed that this was the coelacanth they had dreamed of. Articles describing the fish were published and soon caused a sensation around the world, from New York to New Zealand, from classrooms to laboratories, people were discussing and studying the fish.
"Could it be that the coelacanth caught was the last one?"
Professor Smith had always hoped to see a live coelacanth, but his search was uneven. Soon after, World War II broke out and his expedition was forced to stall. However, the war did not shake Professor Smith's resolve, and once the war was over, he was reintroduced in the long journey in search of coelacanth. For a long time, however, he found nothing. "Could it be that the coelacanth caught was the last one?" There was always such a question in his mind.
Just as Dr. Smith was near despair, good news came one day in December 1952, and a telegram from afar arrived before him: "We have caught a fish like a coelacanth, and we look forward to your arrival." "The telegram was sent by fishermen from the Comoros. Surprised, Dr. Smith rushed to the South African government for help and finally took a military plane straight to the Comoros. Truly, this is Dr. Smith's dream of a coelacanth. The fish, which is 15 metres long and weighs 58 kilograms, has been injected with formalin and then salted, awaiting Professor Smith's arrival. Since then, until July 1955, a total of 15 live coelacanths have been caught in the deep sea of 1519 to 270 meters offshore the Comoros Islands. Only then did Professor Smith dispel his previous concerns.
Discovery activities don't stop there. In 1997, another closely related species of coelacanth was discovered on the Indonesian island of Sulawesi (Celebes). On May 16, 2015, fishermen caught a coelacanth fish near the coast of Zanzibar in northeastern Tanzania that survived for 17 hours in a fish pond at a restaurant near the sea. French, Japanese and Indonesian scientists have dissected the coelacanth and plan to genetically analyze it.
Not long ago, German scientists once again took photos of 6 coelacanths at a depth of 115 to 182 meters in the western Indian Ocean near the Comoros Islands. The coelacanth, which is about 1.5 meters long, sometimes stands upside down, sometimes backstrokes, sometimes swims backwards, and makes some other unusual movements. At first glance, their fins are swinging chaotically, as if they are dancing "disco", and a closer look reveals that their every movement is coordinated with tacit understanding, just like the high coordination of the four hooves when a horse gallops.