Web Builders

Erin Saupe, a graduate student at the KU Biodiversity Institute, studies fossil spiders. She and her collaborators took a spider that died millions of years ago, mapped it using an X-ray, converted the data into a 3D map, and printed a plastic three-dimensional model of the original full-bodied spider: a reproduction that will show her exactly what it looked like, from the legs to the fangs.

Spider from 3D printer

The spiders Saupe studies are often preserved in amber — fossilized tree sap that freezes spiders in time. Sometimes, spiders that have been preserved in amber are easy to examine. But not all amber is golden and translucent. For amber that has turned opaque by gas and dust, you need a tool that can see into the material: a particle accelerator. Once thought capable of inadvertently creating world-ending black holes (since refuted), particle accelerators are some of the biggest, most expensive and high-energy tools available to science. Hurling protons in circles at nearly the speed of light, physicists use particle accelerators to search for data that could shed light on how the universe works. But these high-powered slingshots serve another function: if you hurl electrons, you can create an X-ray thousands of times stronger than that of your dentist. Saupe, her mentors Paul Selden and Paul Tafforeau, and collaborator Vincent Perrichot found promising amber that was full of dust and gas bubbles. It was far too murky to see through. But the team was almost certain that these chunks had good spider and insect specimens — specimens that could provide science with new information about spider and insect evolution. 

At the European Synchrotron Radiation Facility (ESRF) in Grenoble, France, physicists and paleontologists collaborated to do an unprecedented project: use the particle accelerator at the ESRF to obtain high-resolution images of animals trapped in opaque amber. Sending electrons through the amber sample at extreme energies, the scientists were able to capture images of the fossils inside. The results were astounding. Tafforeau and his research team captured images of specimens with fantastic resolution. One of Saupe's spiders was scanned at a resolution of .67 micrometers. About 1,500 .67-micrometer segments could fit end-to-end in a millimeter. 

After obtaining the data from the synchrotron, the paleontologists put the image stacks through a software program called VGStudio Max, creating a 3-dimensional map of the tiny spider’s body. The journey of this information ends in yet another discipline — geology. The KU Geology Department has a 3D printer usually used for recreating soil or geologic models. The machine, which prints in plastic, is capable of turning a digital 3D map like the one of Saupe's spider into a tangible 3-dimensional sculpture. The model will help her understand the evolution of these arachnid web-builders.