Are you scared of spiders? How about scorpions? Scientists may have discovered your worst nightmare. A 100-million-year-old arachnid preserved in amber doesn’t just have eight legs, but the tail of a scorpion too. Sounds like something straight out of one of the Stephen King horror books, right? Yeah, but this creature existed in reality.
Amber mined for centuries in Myanmar for jewelry is a treasure trove for understanding the evolution of spiders and their other arachnid relatives. We have previously told you about another findings made in amber from Myanmar – dinosaur tail was found in already polished piece of amber. Check our previous post, if you want to know more.
It’s the stuff of prehistoric nightmares. Eight legs. Fangs. And a whip-like tail.
Call it Chimerarachne yingi, discovered few years ago arachnid that crawled around rain forests in what is now Southeast Asia more than 100 million years ago during the Cretaceous period. Its remains were found imprisoned in amber, as if Mother Nature herself tried to lock this tiny terror away from the rest of the world.
The arthropod has been named Chimerarachne after Chimera, a monster from Greek mythology who was made of the parts of more than one creature.
Several years ago, amber fossil dealers independently approached two paleobiologists at the Nanjing Institute of Geology and Paleontology in China with what looked like 5-millimeter-long Uraraneida (group which was thought to have thrived between 400 million and 250 million years ago) encased in amber.
One of them, Wang Bo, pulled together a team to look at his two specimens, which they eventually named Chimerachne yingi (“chimera spider” in Latin). The other paleobiologist, Huang Diying, assembled a second team that examined a different pair of these fossils.
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The two groups say they didn’t know about each other until after they submitted their results to the same journal. But, despite some differences, “they draw the same conclusion—that fossil uraraneids, as this group is called, are the closest extinct relatives of spiders,” says Greg Edgecombe, a paleobiologist at the Natural History Museum in London, who was not involved with the work.
So, Chimerachne yingi is not a spider, but rather a relative that lived alongside ancient spiders for millions of years. Its discovery provides insight into the evolutionary history of the creepy crawlers that have spun webs around the planet.
One group’s specimens give a really clear view of the top of this organism and the other, a great look at the underside, spinnerets and all, Huang and his colleagues reported in Nature Ecology and Evolution.
The discovery could help close major gaps in our understanding of spider evolution, says Prashant Sharma, an evolutionary developmental biologist at the University of Wisconsin in Madison who was not involved in the work.
The degree of preservation is exquisite, and the fossils’ anatomy is easy to interpret. The presence of the spinnerets, means they must have originated “very early” in arachnid evolution.
It is believed to have scurried around the undergrowth of the rainforests of Burma during the age of the dinosaurs. Upon inspection, it was found that the creature’s tail was longer that its body – meaning it was used as a sensory device to seek out prey or escape predators. Called a ‘telson’, the tail is seen today in scorpions – but it has never been known before in a spider.
Scientists say it’s possible that the creatures are still scuttling through the forests of Myanmar, where the specimen was discovered. Paul Seldon of the University of Kansas, co-author of one of two papers on the species published in Nature Ecology and Evolution, said in a statement:
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.
The newly discovered species also had fangs – just like today’s arachnids – through which it would inject venom into insects it trapped in pincer like claws. Four fossils were so perfectly preserved scientists could also identify specialised male sexual organs called pedipalps.
Similar to a tiny hypodermic needle they are used to transfer sperm to females. The spider itself is tiny – about 2.5 millimeters in body length. Yet they also have a segmented abdomen and a 3 millimeters long tail, like a scorpion’s whip, Wang and his colleagues reported in their article.
None of the living species from the spider family has a tail, but this feature in itself is not something unusual in the world of arachnids. Among modern arachnids, the presence of an unpaired segmented appendage exists only in two small exotic groups: telephons (Uropygi) and tentacles (Palpigradi).
They are quite far apart on the evolutionary tree from the usual spiders, whose webs you periodically have to sweep out of dark corners. Nowadays, all spiders (and there are more than 46 thousand of them) are devoid of a “tail”, but it seems that their ancestors had one.
“These things appear to be essentially spiders with tails!” says Jason Bond, an evolutionary biologist at Auburn University in Alabama who was not involved with the work about recent discovery in amber. This means that early arachnids had a mix of all these traits, which were selectively lost in their descendants, giving rise to the array of arachnids seen today.
The spider had spinnerets to make silk like modern spiders, but probably didn’t spin the intricate webs we see today.
While the tailed spider was capable of producing silk due to its spinnerets, Paul Seldon said it was unlikely to have constructed webs to trap bugs like many modern spiders.
We don’t know if it wove webs, said the KU researcher.
Spinnerets are used to produce silk but for a whole host of reasons — to wrap eggs, to make burrows, to make sleeping hammocks or just to leave behind trails. If they live in burrows and leave, they leave a trail so they can find their way back. These all evolved before spiders made it up into the air and made insect traps. Spiders went up into the air when the insects went up into the air. I presume that it didn’t make webs that stretched across bushes. However, like all spiders it would have been a carnivore and would have eaten insects, I imagine.
Its scorpion-like tail, Paul Seldon said, was likely used to help the tiny spiders interpret the world around them.
Any sort of flagelliform appendage tends to be like an antenna…It’s for sensing the environment. Animals that have a long whippy tail tend to have it for sensory purposes.
And what is even more amazing, says Bond, is that the amber is only 100 million years old. So these spider relatives hunted side by side with spiders for 200 million years.
Researchers think the spiders lived among the trees because of their amber coffins. Seldon explained:
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.
The fossil sheds light on the origins of modern spiders and their ancient ancestors. The creature fills the gap between ancient arachnids with tails and true spiders, Ricardo Perez-De-La-Fuente of the Oxford Museum of Natural History, told the BBC. He added: “There are many surprises still waiting to be unearthed in the fossil record. Like most unexpected findings in palaeontology it probably brings more questions than answers, but questions are what keep things exciting and push the boundaries of science.”
For now, researchers disagree on the exact placement of the part-spider, part-scorpion critter. Seldon’s team believes it could be one of the first true spiders, while the team behind the second study think it’s an extinct relative.
Take the front of a spider, the end of a vinegarroon and then you put spinnerets on it and that’s our fossil, said Gonzalo Giribet, an invertebrate biologist from Harvard University and an author on one of the papers.
True spider or not, this animal might still haunt your dreams tonight.