Scientists have discovered a new shrimp-like species; blind, tiny and almost translucent in a U.S. cave.

The Bureau of Land Management announced the find Tuesday.

“You never know what you’re going to find down there,” said Jim Goodbar, a senior cave specialist with the bureau. “One of the interesting things about this is these guys, these critters have been down there for tens of thousands of years, millions of years and we’re just getting around to finding them.”

The species of amphipod was discovered about a month ago in a subterranean pool no more than 80 feet (24 meters) from the surface. The location is near Carlsbad Caverns National Park in New Mexico.

The cave had been explored before, but samples had never been taken of the water until a biological inventory was done as part of plans to expand potash mining in the area.

More surveys are planned, Mr. Goodbar said.

Scientists are already making guesses at whether the new species is carnivorous or feeds on bacteria, minerals or vegetative bits that find their way into the water.

“They’re very cryptic. These things are usually found in groundwater, and you can very rarely observe them firsthand.”

The new species has not been named, but officials said it has been grouped with the Parabogidiella genus.

The BLM is working on balancing protection of the new species and the area’s water supply with development of the region’s vast potash resources, Mr. Goodbar said.

The water in the caves is replenished by rainwater soaking down through cracks and crevices in the Earth’s surface and by fresh water from a shallow underground aquifer.

“I think the implications are that we really need to protect the groundwater aquifers because there are species there that live nowhere else on Earth,” Mr. Goodbar said.