Tiny Crayfish Thought to Be Extinct Rediscovered in Alabama

The elusive crustacean resides in a watery cave system in northwest Huntsville.

Scientists from the University of Alabama in Huntsville (UAH) have rediscovered a small, rare crayfish thought to be extinct for 30 years. The team, led by assistant professor Dr. Matthew L. Niemiller, found Shelta Cave Crayfish in Huntsville's Shelta Cave—the crustacean's only home—during snorkeling excursions in 2019 and 2020.

The elusive crayfish's watery home is a 2,500-foot cave system that's owned and managed by the National Speleological Society (NSS) in northwest Huntsville.

"The crayfish is only a couple of inches long with diminutive pincers that are called chelae," Dr. Niemiller said in a news release. "Interestingly, the crayfish has been known to cave biologists since the early 1960s but was not formally described until 1997 by the late Dr. John Cooper and his wife Martha."

Dr. Cooper studied the aquatic life in Shelta Cave in the late 1960s and early 1970s. At that time, Shelta Cave's aquatic ecosystem boasted at least 12 cave-dependent species, including three species of cave crayfishes.

"No other cave system to date in the U.S. has more documented cave crayfishes co-occurring with each other," Dr. Niemiller said.

Shelta Cave Crayfish
Courtesy University of Alabama in Huntsville

According to a UAH news release, the cave's aquatic ecosystem crashed sometime in the early 1970s. The crash is thought to have been caused by a gate that was installed to protect the cave's grey bats.

"The initial design of the gate was not bat friendly, and the bats ultimately vacated the cave system," Dr. Niemiller explained. "Coupled with groundwater pollution and perhaps other stressors, that all may have led to a perfect storm resulting in the collapse of the aquatic cave ecosystem."

Only 115 Shelta Cave Crayfish individuals were confirmed between 1963 and 1975. Since then, only three have been confirmed: one in 1988, one in 2019, and a third in 2020.

Shelta Cave Crayfish
Courtesy University of Alabama in Huntsville

Little is known about the crayfish, but one thing is certain: keeping them around is good for all of us.

Dr. Niemiller is currently conducting the first-ever comprehensive assessment of groundwater biodiversity in the central and eastern United States. Knowing the health of the tiny creatures that are dependent on groundwater is important for several reasons.

"Groundwater is critically important not just for the organisms that live in groundwater ecosystems, but for human society for drinking water, agriculture, etc.," Dr. Niemiller says. "The organisms that live in groundwater provide important benefits, such as water purification and biodegradation. They also can act like 'canaries in the coal mine,' indicators of overall groundwater and ecosystem health."

Hang in there, little guys!

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