They are not bacteria, animals or fungi, any branch of biology identified by Darwin has no place for them, and indeed these Earth creatures have succeeded in causing pain to scientists. because it is not possible to classify them.
In 1998, a team of researchers at the University of Essen (now merged with the University of Duisburg) observed a mysterious parasite infected with amoeba. This phenomenon confused the scientific community at the time, who speculated that this could be an archaea or a distant relative of bacteria.
In 2013, Jean-Michel Claverie and his team at Aix-Marseille University in France described a giant new virus called the Pandora virus. In a subsequent document search, they discovered that the German researchers encountered a similar life form, but did not realize the nature of the virus.
Most known viruses are extremely small in shape, their biological structure contains at most a few hundred genes, while Pandora virus is completely different, it has a very large size, biological shape. When viewed through a microscope it looks like an oval pot and contains thousands of genes. What’s even more surprising is that 93% of those genes are unknown to humans, so it can be seen that this virus is completely different from any microorganism or life form known. known otherwise. So it’s not surprising that scientists have a headache because they can’t classify them.
In biology, phenotypic simplicity doesn’t mean easy to understand: it’s an organism made up of only one cell, but researchers don’t know where to place it in the phylogenetic tree.
Collodictyon triciliatum was first found in alluvium from a lake near Oslo, Norway in 1865. Kamran Shalchian-Tabrizi and colleagues at the University of Oslo in Norway believe this oval cell looks like a common amoeba, but in reality, far from that appearance, they hide many things that humans have never known.
If its DNA is classified in the eukaryotic domain because its DNA is enclosed in the nucleus, its morphology does not correspond to any species of this organism.
Thus, Collodictyon triciliatum may have been an intermediate form before eukaryotes formed two major branches, unicorns (Unikont) and unicellular diatoms (Dinoflagellata).
This was further confirmed in genetic analysis. In other words, scientists need to create a separate classifier for this cell type of organism. The discovery of Collodictyon triciliatum gave people a deeper understanding of eukaryotic evolution.
In 1977, when British paleontologist Simon Conway Morris saw these strangely shaped fossils from the Burgess shale mine in Canada, he thought the creatures were peculiar and unlike any other. which have been found before.
They were later named Hallucigenia sparsa (meaning “daydreaming”) and described as follows: tubular, standing bodies with 7 pairs of “long legs” on their backs, with a row of “tentacles” ” in front and 7 pairs of pincer legs below. It is a small creature, measuring a few centimeters in length and only thicker than a hair. Scientists have described this mysterious creature before, but because its head and tail are similar, they have not been able to identify the detailed features.
However, determining the taxonomy of this creature has become a nightmare in the world of paleontology, because scientists can’t figure out where it came from, nor how it ate and moved. they.
It wasn’t until 1991 that Lars Ramskold and Hou Xianguang, who was also working at the Swedish Museum of Natural History at the time, suddenly thought of reshaping them and reconstructing the pigment showing 7 pairs.” long legs” on the back are actually spikes and act as body protection.
The change of perspective allows these “strange insects” to blend in with the cephalopods and trace their ancestry: these strange land animals look like worms, but they are actually related to arthropods (including insects).
A study of the structure of the strange worm’s claw published in the summer of 2014 seems to provide strong support for this hypothesis…
According to later research, scientists discovered that Hallucigenia sparsa is a common ancestor of velvet worms and is a member of the ecdysozoan group of animals (including arthropods, velvet worms, water bears). They date back to the Cambrian boom, when most major animal groups first appeared on Earth.
These sea creatures look like mushrooms, but they are animals. Jorgen Olesen of the National Museum of Natural History in Copenhagen, Denmark, and colleagues named it Dendrogramma and tried to figure out what kind of animal it was.
The 18 existing specimens of Dendrogramma were collected at depths of 400 to 1,000 meters in Australian waters in 1986. Their shape is reminiscent of jellyfish and their close relatives because both have a mouthpiece that can be used used for both food absorption and excretion.
However, other than that, Dendrogramma has no tentacles, sensors or other features associated with jellyfish. And it seems that the classification of this species has so far been a headache for scientists. Should dendrogramma be considered a separate branch of the phylogenetic tree?
DNA analysis can give us some hints. However, after 28 years of storage in special solutions, any molecular testing becomes impossible. And at the moment it is still not possible to find a new specimen of this species.