Smithsonian.com

The red and aquamarine highlights, and its giant size, set this crayfish apart (Photo courtesy of Carl Williams)

Crayfish, crawfish, crawdads. Call them what you will (tasty?), there are some 600 species found all over the world, and half of those in the United States and Canada. But if you’re looking for the real hotspot of crayfish diversity, head to Tennessee or Alabama. That said, scientists weren’t expecting to find a new species in Shoal Creek in Tennessee; aquatic biologists had been studying life in that little waterway for decades.

The tale starts in 2009, when Eastern Kentucky University biologist Guenter Schuster received some photos of a large crayfish found in Shoal Creek and shared them with Chris Taylor, an aquatic biologist at the University of Illinois. The crayfish had bearded antennae covered in bristly setae that enhance their sensory capabilities, and it looked a lot like Barbicambarus cornutus, a species that lives about 130 miles away from the creek in Kentucky and can grow as big as a lobster. Schuster and Taylor thought that perhaps a fisherman had brought the crayfish to Tennessee in a bait bucket. But when a colleague in Tennessee told them he’d found another giant crayfish in the creek, they had to check it out for themselves.

After a couple hours of wading through the water and upturning boulders, they struck the crayfish jackpot. Beneath a big, flat boulder under a bridge they found a male twice the size of any other crayfish they’d seen that day. And under an ever bigger rock they spotted a female. DNA analysis showed that these large Shoal Creek crayfish were their own distinct species, now named Barbicambarus simmonsi; a description of the new species appears in the Proceedings of the Biological Society of Washington.

The scientists aren’t sure why no one noticed the large crustacean before. “If you were an aquatic biologist and you had seen this thing, because of the size and the setae on the antennae, you would have recognized it as something really, really different and you would have saved it,” says Schuster. However, it appears that these crayfish are not common (only 5 have ever been caught) and their preference for living under large rocks in deep water may have made them easy to overlook, especially in times of high water.

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