The discovery of a new species of giant crayfish under a rock in Tennessee's Shoal Creek, which has been studied for 50 years, just goes to show that you don't have to travel to exotic rivers and wetlands in Asia and Africa to find species that are new to science.

The southeastern United States is, in fact, a hotbed of aquatic species diversity, with small populations of unique species living among the hundreds, if not thousands, of springs, rapids, pools, rivers, and wetlands that carve through and pockmark the region, especially in the southern Appalachian Mountains.

The Southeast is home to the largest array of freshwater mussels on Earth; an abundance of freshwater snails, crayfish, and turtles; and nearly 700 of the approximately 1,000 species and subspecies of U.S. freshwater fish.

(Read about freshwater biodiversity in the southeast in National Geographic magazine.)

"We spend millions of dollars every year on federal grants to send biologists to the Amazon, to Southeast Asia—all over the world looking for and studying the biodiversity of those regions," said Eastern Kentucky University biological sciences professor Guenter Schuster in a statement. Schuster is one of the biologists who found the new species. "But the irony is that there's very little money that is actually spent in our own country to do the same thing. And there are still lots of areas right here in the U.S. that need to be explored."

Photos: New Giant "Bearded" Crayfish Species

Scientists have found a unique new species of crayfish in Tennessee and Alabama that is twice the size of other crayfish in the southeastern U.S.