Paleontologist Confirms Fossilized Spider as Painted Crayfish Fossil

duped by clever forgery of fossilized spider

By Jonny Lupsha, Wondrium Staff Writer

An alleged new species of fossilized spider is really a crayfish with legs painted on it, Science Alert reported. The fake spider was the subject of a paper published this year, but it has since been debunked. Paleontology tools helped crack the case.

Image of fossilized spider
Photograph and line-drawing of Mongolarachne chaoyangensis (Cheng et al, Acta Geologica Sinica, 2019)

Invertebrate paleontologist Paul Selden of The University of Kansas exposed the fraud after reading about the supposed new species of spider. The article in Science Alert said that he and his colleagues borrowed the spider and found multiple irregularities compared to most preserved arachnids. They used paleontological tools like an ultraviolet microscope to photograph the creature in sections and show it as a fluorescent image.

“These images returned four main fluorescent colours: white, which likely indicated a mended crack; blue, which is the mineral composition of the host rock; red, indicating actual fossilized material; and yellow,” the article said. “That yellow fluorescence […] is most likely created by oil-based paint.”

These and other paleontology tools help illuminate the mysteries of the prehistoric world.

The Cruder Tools of the Trade

Finding a fossil to extract from the field often begins with a geological map, a trained eye, and a bit of luck.

“A good start is to eyeball the ground for fragments of fossils in what we call ‘float,'” said Dr. Stuart Sutherland, Professor in the Department of Earth, Ocean and Atmospheric Sciences at The University of British Columbia. “These are loose pieces of rock that have been eroded from an outcrop that actually contains the fossils you’re looking for.”

Many wonderful specimens have been found this way, according to Dr. Sutherland. Once found, he said, collecting the fossils is often a straightforward and practical task.

“For most, like the shells of various marine creatures, fossils can often be collected by the application of hammer, chisel, crowbars, and just a little muscle, making sure your eyes are protected by safety glasses, as many of the rocks will have a high silica content and splinter into dangerous shards when hit.”

Depending on the size and volume of the fossil and its host rock, paleontologists even use jackhammers and backhoes to access their prize. If it’s large enough, it will be covered in plaster on-site so it can be transported safely back to a lab and pried loose.

On the Slab in the Lab

“Back at the lab, in the case of the larger specimens, the fossils have their plaster jacket removed, and the long and very careful process of removing the fossils from the rock matrix will begin,” Dr. Sutherland said. “A number of tools are used for this, including the air scribe, which acts a bit like a miniature jackhammer, chipping away at the rock matrix.”

Sometimes the air scribe will help pop the fossil free from its host rock. Otherwise, a slew of other tools are used for closer cuts on stubborn specimens, slowing the job down tremendously.

“If a fossil is too fragile, or the matrix is too hard, fossil preparators may use gentle grinding tools to help separate them from the rock,” Dr. Sutherland said. “Once again, though, when getting too close to the fossil, it is only tiny picks and needles that are used to clean up the specimen. As you can see, a steady hand and a lot of patience is required for this job.”

Hammers, chisels, jackhammers, and other field tools help bring fossils to labs for further cleaning and removal from ancient rock. Air scribes, picks, needles, and grinding tools help finish the job and prepare fossils for studying while specialized microscopes and mass spectrometers let scientists analyze them for insights into the prehistoric world.

Paintbrushes and oils, however, are generally not among them.

Dr. Stuart Sutherland contributed to this article. Dr. Sutherland is a Professor in the Department of Earth, Ocean and Atmospheric Sciences at The University of British Columbia (UBC). He earned an undergraduate degree in geology from the University of Plymouth and a Ph.D. in Geological Sciences from the University of Leicester.