Few people know of its existence, but Bobcat Cave in Huntsville, Alabama, is one of the most unique ecosystems in the United States. With a mapped length of nearly 1,490 feet, the underground limestone network is only passable through low, water-filled tunnels and mud-slick crawlways. Despite these claustrophobic confines, researchers have spent nearly 40 years regularly monitoring Bobcat Cave for its rare resident, the Alabama cave shrimp (Palaemonias alabamae). The tiny, extremely endangered species of nearly translucent freshwater crustacean is only documented in cave systems stretching between Alabama and Tennessee, making them invaluable to conservationists.
But after recent expeditions into Bobcat Cave, researchers now say the small shrimp lives beside an unexpected neighbor. According to their recent study published in the journal Scientific Reports, biologists at Auburn University discovered a pale, eyeless fish measuring less than two inches long. Although diminutive, the new species now has an imposing name: the demon cavefish (Demogorgonichthys arcanus). What’s more, the subterranean dweller is so genetically distinct that it earned its own genus—and that likely makes it one of the rarest fish in the world.
“Most of the time when we discover new species, we are finding differences within organisms we already knew were there,” Jonathan Armbruster, a study co-author and curator of fishes at the Auburn University Museum of Natural History, said in a statement. “This was different. This was a new discovery that had not been seen before, and that is really rare.”
The demon cavefish is related to the more common southern cavefish species (Typhlichthys subterraneus) as well as the harder-to-find Alabama cavefish (Speoplatyrhinus poulsoni). However, it possesses some key differences. Aside from its unique snout, body shape, and a lack of coloration, the demon cavefish lacks part of a key gene tied to light sensitivity.
“The Southern Cavefish clearly has some kind of response to light. With this fish, we don’t see that,” said Armbruster. “Part of the rhodopsin gene is missing, so it is no longer functional.”
The demon cavefish’s fearsome scientific name may recall the monstrous Demogorgon from Netflix’s hit series, Stranger Things, but the reference is actually even older. Study co-author and University of Alabama biologist Pamela Hart has long kept a running list of mythological, underground creatures as potential inspirations for future species names. The Demogorgon’s origins trace back not to 1980s Hawkins, Indiana, but to Ancient Greece. Seventeenth century poet John Milton even described it in Paradise Lost.
Its specific name, “arcanus,” is Latin for “hidden” or “secret,” which is appropriate. So far, researchers have only seen around 20 demon cavefish at a time.
“It may have been living down in the aquifer and only recently made its way up,” Armbruster said. “Or it may have been there before, and we just never saw it.”
Like the Alabama cave shrimp, biologists are using the demon cavefish as another example of the importance of strengthening conservation efforts in these delicate and unique ecosystems.
“It may have been living down in the aquifer and only recently made its way up,” explained Armbruster. “Or it may have been there before, and we just never saw it.”