Scary spider fossils: Or, when a fly swatter won’t cut it
By Cat Viglienzoni — April 22, 2011
My teacher alerted me to a very fascinating and creepy-crawly recent discovery: the largest fossilized spider found yet.
If you’re someone like me who is afraid of spiders and vanquishes all arachnids within my house (with a special focus on my room), the mere thought of this spider is terrifying. My weapon of choice is a fly swatter (with a vacuum cleaner on standby in case the spider is in a hard-to-reach place). However, that would be a poor weapon against this fossilized Shelob.
The leg span on the spider is 15 cm long (6 inches!) – if that sounds small, reconsider what that would look like if it was sitting on your shoulder. It’s part of the group of spiders called golden orb weavers, which are known for their their webs made from a tough gold silk. The webs the females weave are often about 5 feet long and glisten in the sunlight (hopefully this means you’d see it before walking into it?).
This Nephila jurassica, as they have called it, is a female spider who doesn’t have the largest body, but when her leg span is factored in, she becomes the largest known fossilized spider. This fossil was found in the inner Mongolia region of China. Today, the golden orb species are found worldwide in tropical and sub-tropical regions. (Thankfully, this does not include anywhere I live.) It’s estimated at around 165 million years old – far older than the previous oldest (35 million years old).
Because of this finding, this makes this spider genus the oldest – reaching back to the Jurassic Period. (So the next Jurassic Park, if they go there, should include one of these!)
If you’re wondering how this spider met her demise… it took a natural disaster to kill her. The spider was encased in volcanic ash at the bottom of a lake. They’re hypothesizing that the ash from the volcano pulled her from her big web and smothered her. We can thank this particular ending for the remarkable preservation of the spider, right down to the hairs on her legs. (Those hairs are used to detect vibrations, if you’re curious.) It was because of that near-perfect preservation that scientists were able to identify the genus and species of the spider with certainty.
One thing that’s particularly cool about this species is the size of the females versus the males. It’s called sexual dimorphism, and for this spider species, it means the male is very small and the female is very large in comparison. Whether that was true in the Jurassic Period has yet to be determined, but a male of the species found in Spain from the Cretaceous Period was normal-sized.
All Lord of the Rings jokes aside, that spider preyed on medium to large insects, not hobbits. But there is a terrifying picture of one of these present-day spiders devouring a bird in this article.
I’m wondering what this does to the news from a couple years ago about the world’s oldest spider web being found preserved in amber (140 million years old, Cretaceous period). I would assume that finding a fossilized version of this web-weaving spider would then preclude the assumption that spider webs existed during the Jurassic Period as well.
As I went about my searches for images of this particular spider, I came across these ones of spider art in a public place. LARGE spiders in public places…
Anyway, that’s my second post on spiders. If you’d like to hear about one that’s attracted to humans’ scent, I invite you to check out my first blog post.
(Photos courtesy: BBC, AP Images)