Researchers Discover 100-Million-Year-Old Spider with Tail 'Frozen' in Amber

The newly-discovered spider also has fangs and dates back to the era of famous dinosaurs like Tyrannosaurus rex and the Iguanodon.

Anyone who hates spiders won't enjoy the latest major discovery of prehistoric creatures. An international team of researchers discovered a new species of arachnid that looks like a spider with a tail and fangs. The team found the creature perfectly preserved in amber in Myanmar (formerly Burma), and they've dated the spider to be roughly 100 million years old. 

Luckily for everyone who hates spiders, these new animals were not very big according to the researchers. They only measured 2.5 millimeters in length with a tail longer than its body at 3 millimeters. The dating of the spider places it at the mid-Cretaceous age. This means that the Chimerarachne Yingi spiders lived alongside large herbivores like the Iguanodon and hadrosaurs, and even larger predators like the Tyrannosaurus rex. It takes its name from the Greek mythological beast the Chimera, a hybrid composed of multiple animals. 

Researchers Discover 100-Million-Year-Old Spider with Tail 'Frozen' in Amber
Source: University of Kansas | KU News Service

Finding the creature trapped in amber clued researchers like Paul Selden of the University of Kansas Paleontological Institute and Department of Geology into where exactly these ancient arachnids lived. 

"We can only speculate that, because it was trapped in amber, we assume it was living on or around tree trunks," he said. "Amber is fossilized resin, so for a spider to have become trapped, it may well have lived under bark or in the moss at the foot of a tree."

Selden also noted that increased production of amber in northern Myanmar gave the team a great hint as to where they might potentially find more prehistoric creatures. 

"There's been a lot of amber being produced from northern Myanmar and its interest stepped up about ten years ago when it was discovered this amber was mid-Cretaceous; therefore, all the insects found in it were much older than first thought," said Selden. "It's been coming into China where dealers have been selling to research institutions. These specimens became available last year to Nanjing Institute of Geology and Paleontology."

In addition to the tail and the fangs, this new spider has male pedipalps, four walking legs, and silk-producing spinnerets at the rear. What fascinated the researchers most, however, was the existence of the tail -- something no other known spider has had. (The team noted in a press release that the anal flagellum of certain spiders do not constitute as a true tail.) 

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"The ones we recognized previously were different in that they had a tail but don't have the spinnerets," said Selden. "That's why the new one is really interesting, apart from the fact that it's much younger -- it seems to be an intermediate form. In our analysis, it comes out sort of in between the older one that hadn't developed the spinneret and modern spider that has lost the tail."

Spider's tail potentially served as a form of antenna

The team theorized that the tail potentially served as a form of antenna for sensing its environment, particularly because the tail was thin and whip-like. 

Researchers Discover 100-Million-Year-Old Spider with Tail 'Frozen' in Amber
The dorsal view of the spider encased in amber. Source: University of Kansas | KU News Service

Selden said this discovery isn't the end of the ancient spider. He mentioned that it could be possible that these tiny spiders still exist in Myanmar today -- or at least their descendants. 

"We know a lot about the Burmese biota during the Cretaceous," he said. "It was a pretty good tropical rainforest, and there are a great many other arachnids we know were there, particularly spiders, that are very similar to the ones you find today in the southeast Asian rainforest. It makes us wonder if these may still be alive today. We haven't found them, but some of these forests aren't that well-studied, and it's only a tiny creature."

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The entire paper was published in the most recent edition of Nature Ecology & Evolution.

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