This pale, eyeless species of catfish is only found living deep below the surface of the Earth — a fact of its distribution that suggested its official scientific name “Satan” in 1947.

Only a handful of specimens of Satan eurystomus have ever been collected, and the last living ones were found in the 1980s.

But a team from the Academy of Natural Sciences of Drexel University’s Ichthyology Department, along with a researcher at the University of Texas in Austin, recently obtained full-body 3D X-ray CT scans of some of the known specimens. With these high-resolution images the scientists can compare Satan among related catfish species.

“This fish has not been collected in more than 30 years and there are only 14 specimens in collections, making it really difficult to understand to what species they’re related,” says Mariangeles Arce H., collection manager in Ichthyology at the Academy.

Arce H. co-authored a paper on the scanning that appeared in the Proceedings of the Academy of Natural Sciences of Philadelphia. Professor emeritus John Lundberg was lead author of the paper along with contributions from additional co-authors Kyle Luckenbill (research assistant and imaging specialist) of the Academy and Dean Hendrickson of the University of Texas in Austin.