Congratulations to science on discovering an even more terrifying spider. OK, so Chimerarachne yingi isn't quite a spider and lived 100 million years ago. But still. The discovery of the apparent spider ancestor—four individuals of which were found trapped in amber from Myanmar—was revealed in a paper Monday in Nature Ecology & Evolution. While C. yingi shares a lot of characteristics with modern spiders—eight legs, fangs, silk-producing spinnerets—it has one noticeable trait missing from its descendants: a hairy tail longer than its body, according to a press release. National Geographic reports the creature may have used the tail to sense its environment. The paper's co-author, Bo Wang, says tails may have disappeared as spiders transitioned from hunting their prey to waiting for it in webs.
Researcher Paul Selden says the 2.5-millimeter-long C. yingi is interesting because it represents a bridge between the tail-having uraraneids from 290 million to 380 million years ago and modern arachnids. No living spiders have tails (though the ones in your nightmares may after reading this story), but spider-like animals called vinegroons—described by the Washington Post as "a group of nightmarish scorpion-looking creatures"—do. Selden adds that it's possible C. yingi still has tailed descendants living in Myanmar because of the remote area where the amber was collected. "We haven't found them, but some of these forests aren't that well-studied, and it's only a tiny creature," he says. (Meanwhile, a study last year found spiders eat more meat than all humans combined.)