Fossil hunters in Korea discovered long-dead spiders that were kept in the rock. And to the delight of the scientists, the eyes of the arachnids still reflect – about 110 million years after the death of the creatures.
It is rare that insects and arachnids, which are much more brittle than shelled sea creatures, are petrified in rocks. But for unknown reasons, some of these spiders have petrified, and the unique shape of their eye structures continues to reflect light – even in their fossilized form.
The reflective eye structure is called Tapetum and is often used by creatures hunting in the dark.
"Therefore, night hunt predators tend to use this other eye," said Paul Selden, director of the Paleontological Institute at the Biodiversity Institute and Natural History Museum of Kansas University. "This was the first time a tapetum had found a fossil, this tapetum was in the shape of a canoe – it looks like a Canadian canoe."
Today's wolf spiders use the same eye structures for hunting, Selden added.
One mystery remains: how were the spiders petrified? Their fossilized bodies were found in a rocky outcrop filled with fish and other marine life – but spiders do not live in the water.
Selden said. "Normally they would float, but here they sank, and that kept them away from decaying bacteria – it could have been an oxygen-poor condition."
Selden and his Korean counterparts – who actually discovered the old spiders – can now name the curious fossils that were only found because Korean land is often dug up, like this Scientists and Fossil – captivating excavations to see what ancient novelties are hidden in the earth's crust.
"They carve the hills to create a shallow area, and there are temporary excavations as they cut and build a factory or whatever – that's where they found these fossils," Selden said  Uploads% 252fvideo uploaders% 252fdistribution Thumbs% 252fimage% 252f85981% 252f120f5e1f 7646 4214 AC05 8e5ec6b6f03d.png% 252foriginal.png? Signature = xh6iamctwja5xroqir8hv1skfzy = & source = https% 3a% 2f% 2fblueprin t api production.s3.amazonaws ” src=”https://mondrian.mashable.com/uploads%252Fvideo_uploaders%252Fdistribution_thumb%252Fimage%252F85981%252F120f5e1f-7646-4214-ac05-8e5ec6b6f03d.png%252Foriginal.png?signature=Xh6iamCtwjA5xROqIR8HV1SKfZY=&source=https%3A%2F%2Fblueprint-api-production.s3.amazonaws.com” data-fragment=”m!0011″ data-image=”https://mondrian.mashable.com/uploads%252Fvideo_uploaders%252Fdistribution_thumb%252Fimage%252F85981%252F120f5e1f-7646-4214-ac05-8e5ec6b6f03d.png%252Foriginal.png?signature=Xh6iamCtwjA5xROqIR8HV1SKfZY=&source=https%3A%2F%2Fblueprint-api-production.s3.amazonaws.com” data-micro=”1″/>