Crayfish Diversity

The flora and fauna of North America is among the best-studied on Earth, yet scientists continue to make remarkable discoveries in our own backyard. Just this month, scientists announced the discovery of a giant crayfish—the Tennessee Bottlebrush Crayfish--from Shoal Creek on the Alabama-Tennessee border. However, this new species is remarkable only because of its size--up to 5 inches long! Since 2000, at least 33 species of crayfish have been described from North America, including at least five from Tennessee.

This represents most of the diversity of crayfish worldwide. The family Cambaridae, which most southeastern species belongs to, has around 430 species, of which seven occur in east Asia and the rest in eastern North America. Crayfish from west of the Continental Divide are in the family Astacidae (~16 spp.), which also occurs in Europe and the Mideast. A third family, the Parastacidae (~180 spp.), occurs in the Southern Hemisphere.

Our knowledge of many invertebrate groups is still in its infancy. The southeastern US has extremely diverse communities of aquatic snails, mussels, caddisflies, and many other insects. Even well-studied groups like freshwater fishes and amphibians still see new species described on a regular basis. Because these animals serve as an important component of aquatic food chains and affect ecosystem structure and function, it’s critical that we continue to study and conserve them.

-Dr. Dave Neely