The fossilized remains of ancient insects are regularly found in amber. Inclusions allow scientists to study the past of our planet and how various types of living things evolved over time. So, during the excavation of amber in Myanmar (Southeast Asia), a bizarre creature was discovered, at least 100 million years old, which looks like a scorpion and a spider. During the excavation, two independent groups of researchers found four specimens with arachnids, which, researchers believe, will help scientists fill in the gaps in understanding the evolution of spiders. The work was published in the journal Nature Ecology and Evolution.
How did arachnids develop?
Arachnids or arachnids belong to the class of arthropods. Researchers described at least 114 thousand species. The most famous representatives are spiders, scorpions and ticks. In this case, only spiders are famous for the presence of spinnerets – parts of the limbs that help them release the web. Given that spiders live on our planet for about 300 million years, they had enough time to find their niche in the animal world. So, over time, male spiders acquired a smooth back, unlike scorpions with their segmented backs, which they inherited from their ancestors who lived on Earth 450 million years ago. The fossil discovered in Myanmar clearly illustrates the evolution of arachnids – a creature in amber can be called a chimera: the head of a spider, but the end of the body is just like a scorpion, only with legs. Like a scorpion, the fossil has a long, whip-like tail. However, researchers believe that the tail of the ancient arachnid did not sting and looks more like an antenna.
What other relatives of arachnids have scientists found?
In 1989, scientists discovered an ancient fossil whose age was clearly greater than the age of modern spiders. Only in 2008, paleontologists found out that this arachnid was not a real spider, but its distant relative. The find was categorized as Uraraneida, an extinct species of spiders that researchers believe existed on Earth 400-250 million years ago.
The study of Uraraneida, stuck in amber, was carried out by two independent research groups. As a result, both teams concluded that creatures locked in petrified resin belong to a different arachnid genus. In several images of the obtained samples, one can see the upper and lower parts of the body of arachnids. The degree of fossilization provided transparency when viewing, which allowed researchers to more easily identify the anatomy of the spider.
The most striking difference between the find and modern spiders is the presence of a long segmented tail like a scorpion. This led many researchers to the conclusion that the ancient arachnids possessed traits not characteristic of them. In addition, the age of amber in which these creatures are stuck is about 100 million years.