It's Halloween and what could be more fitting than an eyeful of dead, mummified spiders? There's never been a better time to get cozy with ancient arachnids, according to Paul Seldon of the Paleontological Institute at the University of Kansas.
He has been using some of the latest imaging technology -- like this digitally-produced, 3-D CT-scan image -- to give the eight-legged ancestors of today's spiders their first real close-ups. The following are a few othershe presented
on Oct. 29 at the annual meeting of the Geological Society of America in Denver.
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The best way for a spider to get preserved through the ages is in amber -- which is basically tree sap in which the spider got fatally mucked up. These give some nice photo ops as well, but can be tricky because they are small and, well, stick in amber.
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Careful processing of multiple images can bring a lot of details of these Cretaceous spiders into focus that might otherwise be lost to the narrow focus plane of a microscopic view.
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Using X-ray CT-scans, the amber spiders can be digitally “removed” from amber and imaged in three dimensions without harming the actual specimen.
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Much greater resolution of even smaller spiders is done with synchrotron radiation.
Spiders are also preserved directly in sediments, like this Jurassic spider found in rocks from China.
The Chinese plectreurid spider has left behind an amazing amount of detail.
A 304-million-year-old fossil discovered in Eastern France shows primitive living harvestmen -- more commonly called daddy longlegs -- had one more pair of eyes than they do today.
The ancient harvestmen had a pair of eyes along the middle of the body -- like their modern counterparts -- but they also had a pair of eyes on the side of the body. The findings were reported by researchers from the American Museum of Natural History and the University of Manchester, in the journal Current Biology.
Scientists studied the fossil using high-resolution X-ray imaging at the Natural History Museum, London.
"Our X-ray techniques have allowed us to reveal this fossil in more detail than we would have dreamed possible two decades ago,” said Russell Garwood, a research fellow at the University of Manchester and a lead author on the study, in a release.
Though Harvestmen have eight legs and are categorized as arachnids, they're not spiders. They're more closely related to scorpions.
The scientists also examined the expression of an eye-stalk growing gene in harvestmen embryos. The embryos briefly express the gene for the second pair of eyes. But by the time they hatch, the daddy long legs' second pair of eyes are long gone.
Photo: Modern daddy longlegs have just one set of eyes, unlike their primitive ancestors. Wikimedia Commons/Thomas Bresson