After its discovery, the strange appearance of the hallucinogenic worm caused scientists a headache. Not only the front and back, but also their heads and tails are very confusing. In 2015, humans were able to see and restore its original body.

About 530 million years ago, the Cambrian eruption occurred unexpectedly. Large creatures such as arthropods, enterophytes, demodexes, chordates, and other creatures suddenly appeared on Earth. As promised, the ancestors of almost all living animals today appeared at this time. The former single-celled world has now become a growing landscape where many species of animals coexist.

150 years ago, this great event of biological evolution confused Darwin. He was surprised and could not find a way to explain this phenomenon. Darwin therefore had to admit that he would use it as strong evidence against his theory of evolution. To this day, the “mystery of the eruption of Cambrian life” is still considered “Mount Everest” in academic circles, and countless scientists have worked hard to find the cause of this event.

The Cambrian can be divided into Early Cambrian, Middle Cambrian and Late Cambrian. Walcott, an American paleontologist at the time, studied mainly the geographical layers of the early Cambrian.

Fortunately, in July 1909 he discovered the Burgess Shale in Canada.

But it is a pity that Walcott did not spend much time here due to lack of manpower and other reasons; From there, however, he still found more than 60,000 fossil specimens of the organism.

He did not analyze them carefully and classified them into known categories at the time. The fossil of the main character in today’s article was discovered by Walcott in 1911. When first discovered, it looked like a hairy worm. This form misunderstood Walcott, who classified it as a polychaete known directly.

More than 60 years later, British paleontologist Conway Morris studied fossils again. He was surprised to find that the anatomy of the strange worm was so unique that it did not resemble the biological structure of modern living things.

Generally, after finding a fossil, the first thing researchers need to do is to distinguish its head, tail, front and back before determining its shape. As shown in the picture below, Morris considers the left side to be the head of the particular worm and the right side the tail. At the same time, he calculated that the two-row spikes were evenly distributed over its body, such as the foot, i.e. the front. A single row of thorns is considered the abdomen.

These “tents” in the abdomen cause food to be brought into the mouth. From Morris’ point of view, the strange worm would have a stilt-like gait. He named it the Special Bug – Hallucinia.

As the name implies, this is very strange and difficult to understand. Why can’t it find eyes and mouth on its head? What kind of creature is that? A series of these problems caused headaches for scientists. Since no similarities with existing organisms could be found, many asked to create a new species or branch of biology to describe this animal.

But it seems very strange. The study of this strange worm had no new prospects until the discovery of animals in Chengjiang, Yunnan, China.

On July 1, 1984, Chinese paleontologist How Xiangwang went to the Maoist mountain in search of paleontological fossils. He was a little disappointed for a week without any positive results.

The next day, however, Hao Xianguang discovered a strangely shaped but intact fossil. Excited, he excavated and searched and found three other important fossils.

Upon identification, the fossils were found to belong to the Norom, Gilworm, and Spikeworm. They are all invertebrate fossils from early Cambrian. It’s like opening a door to an ancient biological treasure. Later, scientists such as How Xianguang discovered 10,000 paleontological fossils that were 530 million years old.

These fossils clearly depict to the world the beautiful view of the early Cambrian 530 million years ago. It is one of the oldest, most complete and diverse Cambrian fossils in the world.

The fauna of Zhengjiang is known as “one of the most amazing inventions of the twentieth century” and was officially included in the 2012 World Natural Heritage List.

Of those, more than 90% still have soft tissues such as eyes, appendages, mouth, and gastrointestinal tract. At the same time, there are standing, crawling, eating, digging and other poses, as well as numerous fossil feces, moving marks, and so on.

All of these provide an important fossil basis for studying the anatomy, morphology, function, and lifestyle of animals in early Cambrian.

In addition, Chinese scientists have found that the relatives of the worm Hallucinia do not have long legs.

Between 1911 and 1991, scientists discovered that the fossil specimens Morris had seen were only part of the hallucinogenic worm.

The parts that were previously considered tents are actually legs. The regularly adjusted thorn-like “legs” that were considered the front legs are actually spikes used for self-defense.

But it took another 24 years, in 2015, when a new study was published in the journal Nature, and scientists finally removed the head and tail of this strange worm.

Martin Smith, a scholar at the University of Cambridge, and others analyzed dozens of fossils in the museum collection through electron microscopy.

The part that was previously considered the head is actually the tail and vice versa. But the primary one can tell that its eyes are only sensitive to light and that its eyesight is poor. The spinal teeth are distributed in a circular pattern, helping them to eat plankton. Those particular claws may also have been the weapons of special worms to catch small prey of the Cambrian period.

This time, humans finally gave a reasonable explanation for the appearance of the strange worms. On analysis, they found that the common ancestor of the strange worm and arthropod was similar.

As for the classification of the strange worm, there is still a lot of controversy and research on it.

It is now considered by some scientists to be the ancestor of arthropods, but some scientists believe it may be more closely related to arthropods.