This ancient fossil 'big blue fish' survived the extinction of the dinosaurs, but not plastic waste

"Big blue fish! Big blue fish!!"

On November 23, 1938, when the Nerine was fishing in the Chalumna River in the southeast corner of South Africa, all the crew members were stunned by an incredible big fish. It was about 1.5 meters long and weighed more than 50 kilograms. The fish body was wide, the whole body was sapphire blue, and it had fins similar to the limbs of land animals. Captain Hendrik Goosen said that he had been fishing for half his life and had never seen such a strange-looking fish.

An imaginary depiction of a lacerta in life | JaffaFalcon / Wikimedia Commons

So Captain Gusen immediately called an old friend, Marjorie Courtenay-Latimer, a female curator working at the East London Museum in Cape Province, South Africa, and asked her if she was interested in seeing a "living treasure" that had never been seen before. At that time, the East London Museum was just a small museum, but it was completely different after this unexpected discovery.

The Big Blue Fish of the Century

Even though the captain kept the "big blue fish" as his own, when they arrived at the East London Museum, Mallory was still confused. The legendary royal blue color was gone, and the big blue fish had turned into a "big black fish". Finally, under the solemn promise of all the crew members, Mallory believed that this strange fish was not a fake (at that time, it was common to use spliced ​​animal specimens as new species to deceive the public).

So Mallory immediately contacted fish expert James Smith, but unfortunately Smith was out of town for Christmas. When Smith arrived at the museum, the unique specimen was already decayed, but under the eyes of a professional biologist, Smith still made a judgment - this is indeed a new species that has never been discovered, and it may be a very ancient primitive fish!

A specimen of this ancient fish is kept at the Nante Natural History Museum | Daniel Jolivet / Flickr

So Smith named the strange fish after Marjorie and the Chalumna River where the fish was found, as its genus and species name respectively. This is the "living fossil" among fish - the West Indian Ocean Latimeria chalumnae, also known as Latimeria chalumnae and Latimeria fish.

Ancient living fossil

The terrestrial vertebrates living on Earth today, also called tetrapods (Tetrapoda), have all evolved from ancient fish through an incredible "landing" history.

As far back as the Silurian period 423 million years ago, a group called Sarcopterygii appeared. Unlike most common fish today, their fins were not flat, but more like a "big fleshy arm" with scales. For some unknown reason, a group of "lobe-finned fish" among the sarcopterygii began to use their fins to assist in movement, and environmental pressure gradually made them move towards land. Eventually, our tetrapods appeared in this group, including today's amphibians, reptiles, birds, and mammals.

Tiktaalik | Eduard Solà / Wikimedia Commons

The lacertids had large fin stalks filled with bones and muscle, similar in appearance to the limbs of land vertebrates | Citron / Wikimedia Commons

The limbs of tetrapods evolved from the two pairs of fins of lobe-finned fish. The genetic template is such that we are destined to have only four limbs, both for humans and lizards. It is impossible for Nezha to have "three heads and six arms" or "KFC monster chicken" with six wings and four legs.

Among these lobe-finned fish, the coelacanth is quite special, with most species being fossils and only two living species. Most of them have a spear-shaped tail. The coelacanth appeared in the Early Devonian about 410 million years ago. We once thought that the coelacanth became extinct along with the traditional dinosaurs at the end of the Cretaceous 65 million years ago. What is jaw-dropping is that this lanceolate fish that appeared before Christmas Eve in 1938 belongs to the coelacanth that had been "extinct" for 65 million years!

A coelacanth fossil from the Jurassic period | Hetmanber / Wikimedia Commons

A long childhood

If the century-old appearance of the lanceolabur fish surprised the scientific community, the results of various studies on them were even more surprising. When humans first discovered the lanceolabur fish, they thought it might have a long lifespan, perhaps 50 years. This idea was correct, but it greatly underestimated the length of a "long lifespan".

In June 2021, an article published in the journal Current Biology stated that by studying 12 specimens of West Indian Ocean lacerta in museum collections and examining the ring-shaped calcium structures of their scales (similar to tree rings), scientists discovered that these "prehistoric fish" can live up to 100 years.

In the long years of a century, it takes half or even longer for the lacerta to reach sexual maturity, which may be 50 years for females and more than 60 years for males. It is hard to imagine that such an ancient living fossil fish is still an immature baby fish for most of its life. A lacerta baby has to go through a gestation period of up to 5 years from fertilization to birth!

Embryo of a lacerta fish | Citron / Wikimedia Commons

Scientists speculate that the longevity and slow sexual maturity may be related to the extremely low-energy metabolism of the lanceolatrix. When the lanceolatrix reaches adulthood, its body length can reach 2 meters and weigh 100 kilograms, making it a truly rare "big koi". However, in terms of longevity, compared to the small-headed sleeping shark, the lanceolatrix can only be regarded as a young and beautiful fish.

Surprises ensue

The West Indian Ocean lacerta, which is both bizarre and of great evolutionary significance, has attracted the research of countless scholars and has also produced many "highlights".

After the first West Indian Ocean lanceolatrix was discovered in 1938, everyone wanted to find a more complete specimen, but it took 14 years, and the second West Indian Ocean lanceolatrix was not discovered until 1952. Today, the West Indian Ocean lanceolatrix is ​​classified as critically endangered.

In 1997, another type of latimeria was discovered on Sulawesi Island in Indonesia. The Indonesian latimeria (Latimeria menadoensis) is slightly larger than the West Indian Ocean latimeria. The two species parted ways about 25 million years ago. We have very few specimens of the Indonesian latimeria, which is even rarer than the West Indian Ocean latimeria. In 2011, an Indonesian latimeria was caught in the waters near North Sulawesi Province, Indonesia, and was studied by Indonesian and Japanese scientists the following year. Plastic packaging bags were found in its stomach, which shows the extent to which humans have affected the ancient earth's environment. Even objective and rational scientists have expressed "feeling very sad" about this.

Modern plastic found in belly of ancient lacerta fish | The Palestinian Biological Bulletin (2019)

In the past, people thought that the lacertids were the fish closest to tetrapods, but later genome sequencing and fossil records showed that lungfish were actually more closely related to tetrapods.

If you are interested in this "big blue fish" that opened up new knowledge to mankind in 1938, you can go to the East London Museum in South Africa to see its true self. In the Museum of Vertebrate Paleontology and Paleoanthropology in China, there is also a specimen of the West Indian Ocean lacerta, which was a precious gift from the Union des Comores to the Chinese government in 1982.

This article comes from the Species Calendar, welcome to forward

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