Spider with a 'whippy' tail found preserved in amber

spider tail
© University of Kansas

100 million years ago, spider-like critters had fancy long tails to go with their fangs and spinnerets.

Thanks to Mother Nature’s great freeze-frame device known as amber, scientists have just discovered a remarkable new species of arachnid from 100 million years ago.

Described in a paper published in Nature Ecology & Evolution by an international team of researchers, the new creature, named Chimerarachne yingi, shares traits with a modern spider, like fangs, male pedipalps, four walking legs and silk-producing spinnerets. But it also has a hard-to-miss tail, or flagellum, a feature thankfully missing from today’s spiders. (Or not, see below.)

Several years ago, Paul Selden of the Paleontological Institute and Department of Geology at the University of Kansas discovered similar tailed creatures, though they were lacked the spinnerets. Those much older animals formed the basis of a new arachnid order, the Uraraneida, which would lead the way to modern spiders.

"The ones we recognized previously were different in that they had a tail but don't have the spinnerets," says 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 tail© The ancient arachnid likely used its tail as an antenna. (Photo: University of Kansas)

The mid-Cretaceous amber came from Myanmar and while providing great detail, fails to offer much insight into the daily life of the spider. "We can only speculate that, because it was trapped in amber, we assume it was living on or around tree trunks," says Selden. "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." Adding:

We don't know if it wove webs, 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.

Spider tail© University of Kansas

And on a final note, anyone feeling jittery about whippy-tailed spiders, be careful where you tread. Selden says the spider's remote habitat allows for the possibility that tailed descendants may still be alive in Myanmar's backcountry today.

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