Some people dislike a man's nipples for much use except to distinguish between the front and the back.
But this function alone may be unattractive to many paleontologists.
There was such a prehistoric creature that scientists spent decades figuring out the front and back of it.
It is a grotesque worm that is constructed and is known for its "bizarre daydreams".
Since its discovery, its strange appearance has repeatedly caught scientists around.
Not only the front and back, but even the head and tail were once mistaken.
It was not until the discovery of the Chengjiang fauna in Yunnan, China, that it began to correct.
And it was only in 2015 that humanity was able to see and restore its true form.
About 530 million years ago, a "Cambrian explosion of life" suddenly staged.
Large-scale new life suddenly appeared on the earth, such as arthropods, brachiopods, demodex, and chords.
As if by appointment, the ancestors of almost all the living animals of the phyla came to a "collective appearance".
What was once a bland single-celled world has suddenly become a thriving scene of multiple animal species coexisting.
Early trilobites are thought to be the dominant life form of the Cambrian period
More than 150 years ago, this major event in biological evolution puzzled Darwin.
He racked his brains and couldn't figure out how to explain the phenomenon.
Darwin, therefore, had to admit that it would be used as strong evidence against his theory of evolution.
To this day, the "Cambrian Explosion of Life Mystery" is still regarded as the Everest of the academic world, and countless scientists have worked hard for it.
The Cambrian can be further divided into the Early Cambrian, Middle Cambrian, and Late Cambrian.
An American paleontologist named Walcott studied the geological layers of the Early Cambrian period.
Luckily, he stumbled upon the Burgess Shale in Canada in July 1909.
The period of this shale is about 505 million years ago in the Middle Cambrian Period. Today it is an important evidence of the Cambrian explosion.
But unfortunately, Walcott did not spend much energy here due to insufficient manpower and other reasons;
Nevertheless, he dug up more than 60,000 Specimens of Middle Cambrian fossils.
But without careful analysis, he generally classified them all into the categories known at that time.
The grotesque fossil of the protagonist of our article was excavated by him in 1911.
When it first emerged, it looked like a worm with spiny hairs.
This appearance deceived Walcott and directly classified it as a known polychaetic link creature.
It was nearly three decades before the British paleontologist Convay Morris revisited it.
Morris was surprised to find that the grotesque worm's body configuration was so special that it could not have been a known modern creature.
Generally after the discovery of fossils, the first thing researchers have to do is to distinguish its head and tail and front and back before determining its shape.
Pictured below, Morris sees the spherical part on the left as the head of the grotesque worm and the right as the tail.
At the same time, he regarded the two rows of thorns that were regularly distributed on its body as legs for walking, that is, as the front.
Below it appears that only a single row of thorns is regarded as the abdomen, that is, as the reverse.
These "tentacles" on the abdomen are responsible for delivering food into the mouth.
According to Morris's vision, the grotesque worm walked like it was on stilts.
He thought that only daydreaming could dream of such a bizarre structure, so he named it Grotesque Worm.
As the name suggests, it's so grotesque that it's confusing. Why can't its head find eyes, mouth, etc.? What kind of creature does it belong to?
This series of problems has caused scientists a lot of headaches. Unable to find similarities with living creatures, many people clamored for new orders or even gates for grotesque insects.
A grotesque worm model based on Morris's restoration
But it looks so strange that everyone can't do anything about it, and there is no progress.
It was not until the discovery of the Chengjiang fauna in Yunnan, China, that the study of grotesque insects burst out of new vitality.
However, the significance of the discovery of The Chengjiang Fauna in China is far more than just unveiling the mystery of grotesque insects.
Perhaps there is no ancient fossil group in the world that can be as legendary as it is.
The site of the original excavation of the Chengjiang Hat Tianshan fossil
On July 1, 1984, Hou Xianguang, a paleontologist in China, came to Maotianshan To look for paleontological fossils.
For more than a week, he always came out early and returned late every day, but he was always empty-handed, which was a little disappointing.
At about 3 p.m., Hou Xianguang, who was excavating, lifted his foot, and the heel accidentally cut off a loose rock formation.
At this time, a strangely shaped but intact fossil was revealed.
Excited, he discovered three important fossils.
Later, after identification, it was found that the fossils of Narrow worm, cheek shrimp worm and spike worm were found. They are all invertebrate fossils from the early Cambrian period.
It's like opening the door to a treasure trove of ancient creatures. Hou Xianguang and other scientists have discovered nearly 10,000 fossil specimens of paleontology dating back to 530 million years.
These fossils clearly describe to the world the spectacular scene of the Early Cambrian Period, 530 million years ago.
To date, it is the world's earliest, most completely preserved, and most diverse group of Cambrian fossils.
Narrow worms
Hailed as "one of the most astonishing discoveries of the 20th century", the Chengjiang Fauna was officially inscribed on the World Natural Heritage List in 2012.
It can be said that it is a precious treasure that China dedicates to all mankind. Because of the various animal fossils excavated, it is exquisitely preserved and intact, which is of great scientific value.
Among them, more than 90% also retain marks on soft tissues such as eyes, appendages, mouth organs, and digestive tract.
At the same time, there are standing, crawling, eating, drilling and other postures, as well as a large number of fossil ruins, such as feces, movement marks and so on.
All this provides an important fossil basis for studying the anatomical structure, functional morphology, and living habits of early Cambrian animals.
The cambrian grotesque insect fossils have also been found in the Chengjiang fauna in China, and they are very clear and complete.
In addition, Chinese scientists have found that the close relatives of the grotesque insect do not have long legs.
It wasn't until 1911 and 1984 that scientists realized that we had turned the grotesque worm upside down.
It turned out that the fossil specimens that Morris saw were only parts of the "grotesque worm".
What originally appeared to be only one "tentacle" was actually a pair of feet for walking.
The previously regularly arranged hard spine-like "legs" are spines used to protect themselves.
I can't believe that we've been studying it for so long that we've even turned the front and back of it.
It was another 31 years, in 2015, that a study published in Nature finally distinguished the head and tail of the grotesque worm.
Martin Smith, a scholar at the University of Cambridge in the United Kingdom, and others analyzed dozens of grotesque insect fossils in the museum's collection through electron microscopy.
They finally identified the creature's head and pieced together its body structure, restoring its shape.
In the past, it was thought to be the head of a grotesque insect, but it was actually a fossil formed by the animal's internal organs being squeezed out.
In other words, it is not only upside down and upside down, but also completely reversed.
In fact, there are two rows of antennae, which support the body downwards; and the spikes are upwards!
The eyes and mouth are in the place where people thought it was the tail before.
Under the microscope, they found that not only could they see the eyes, but also the grotesque insects grinning.
This clearly shows that its "tail" is the head.
To sum up, the grotesque worm has a pair of one eyes, a mouth, and its foregulet is covered with plates and has ring-shaped teeth.
However, it is initially speculated that its single eye can only sense light, and its vision is very poor. Ring-like distribution of prickly teeth helps to feed plankton.
Those special claws may also be grotesque weapons to catch small prey from the Cambrian period.
At this point, humans have finally given a reasonable explanation for the shape of the grotesque insect.
Through analysis, they found that the common ancestors of grotesque insect mouths and arthropods were similar.
In addition, they believe that "velvet worms" may be the offspring of grotesque worms, not as previously expected.
The researchers explained that each of their claws resembled an onion, with 2 to 3 layers of stratum corneum stacked on top of each other.
This means that new claws have grown before they are off-table, and this feature is not found in other animals.
Velvet worms
Another study of the claws of the "grotesque worm" suggests that it may have some "kinship" with the Hoshi undead.
As for the classification of grotesque insects, there is still a lot of controversy, and its research is also ongoing.
At present, it is considered by some scientists to be the ancestor of the clawed phylum, but others believe that it may be closer to the arthropod phylum.
It has been hundreds of years since the fossils of grotesque insects have been excavated.
It took scientists 73 years for humans to distinguish between the front and the back, and another 31 years to figure out the beginning and the end.
This is almost unimaginable to us ordinary people.
But for paleontologists, it may be commonplace.
They may have spent their entire lives, and they may not be able to glimpse the secret of a small bug hundreds of millions of years ago.
But it is precisely with the courage and persistence of Prometheus who steals the heavenly fire that the answer to life can be revealed to us.
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