It can only be found in the big spring -- aptly named Big Springs -- that feeds the hidden jewel, Lake Scott.

Today, WildEarth Guardians filed a lawsuit in U.S. District Court in Denver, seeking to force the U.S. Fish and Wildlife Service to reconsider its denial of a request to add the scott's Riffle beetle to the endangered species list.

The insect has long been recognized as an endangered species in Kansas, in part because it is found nowhere else.

The lawsuit is but one of the 36 steps that WildEarth Guardians is undertaking in recognition of the 36th anniversary of the federal Endangered Species Act.

As part of its "BioBlitz Celebration," timed to coincide with the United Nations 2010 International Year of Biodiversity, the group is taking action on an imperiled species each work day for 36 days.

Although unrelated, the observation follows closely on the heels of criticism directed at Interior Secretary Ken Salazar for only adding two species to the Endangered Species list in his first year in office, a new all-time low that even falls short of that under the Bush Administration.

WildEarth Guardians this week took aim at the prairie region, targeting the Texas kangaroo rat, Platte River caddisfly, spot-tailed earless lizard, the prairie chub in Texas and Oklahoma and the Scott riffle beetle.

The lawsuit involving the beetle had been scheduled to be filed today in U.S. District Court in Denver, according to Nicole Rosmarino, wildlife program director for WildEarth.

While Kansas has deemed the insect an endangered species, Rosmarino said the threat might be greatest from the decline of the Ogallala Aquifer, which feeds the spring.

While there's been no evidence that the spring's flow has been reduced, it's not been measured since 1974 either.

That's partly because the area is so small that even measuring the flow could have serious effects on the beetle.

Federal protection has generally been denied in part because its presence is so limited.

"They felt state protection was enough," said Ed Miller, coordinator for the Kansas Department of Wildlife and Parks threatened and endangered species program.

Rosmarino contends federal protection is needed to protect water flowing out of the Ogallala.

"If we don't plan better, the aquifer is going to run dry," she said.

"I guess you'd have to consider that a threat," Miller said of the possibility of Big Springs running dry. "If that spring quits running, that species, as we know it, would probably go extinct."

"This species only occurs in one place on earth," Rosmarino said. "It should and does deserve federal protection."

The WildEarth lawsuit, she said, is designed to get FWS to give the beetle a second look.

Miller said the insect has been hanging on since its listing soon after its discovery in 1978.

"We don't do a lot of research on that because too much research may do more hard than good on this one," he said. "I don't think we do any annual checking."