A previously unknown species of giant crayfish has been discovered by two aquatic biologists in Tennessee. This new species is called Barbicambarus simmonis. It is 5 inches long, which is twice the size of the average crayfish.

The discovery was made in Shoal Creek in Tennessee in 2010 and announced in January 2011.

This isn't a crayfish that someone would have picked up and just said, 'Oh, it's another crayfish,' and put it back, said University of Illinois aquatic biologist Chris Taylor, who discovered the fish.

Guenter Schuster, a biological sciences professor from Eastern Kentucky University, is the co-discoverer of the new species. He

added that the new crayfish is indeed noticeably different from the common crayfish.

More than half of the 600 known species of crayfish in the world are found in North America, according to Chris Taylor.

The discovery of the Barbicambarus simmonis is described in a paper in the Proceedings of the Biological Society of Washington.