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Species Description

Crayfish

Cambarus (Jugicambarus) conasaugaensis


Classification

Phylum: Arthropoda
Subphylum: Crustacea
Class: Malacostraca
Order: Decapoda
Family: Cambaridae

Description

This small-eyed freshwater crayfish has a carapace length that usually ranges between 19.0 and 36.0 mm (0.75-1.4 inches). The carapace and abdomen are olive-green to reddish tan in color. Its rostrum has a thickened margin, but lacks both spines and tubercles (small bumps). The areola is often 2.5-6.0 times as long as it wide and is adorned with 2-4 pits or spots. The areola width appears to vary with the size of the specimen and smaller specimens tend to have broader and shorter areola regions. The chelae (claws on first legs) are fairly short and marked with 5-7 bumps that are arranged in a single row. The chelae are mostly olive green on the dorsal (backside) surface and cream to pinkish orange on the ventral (belly or bottom) side. The uropods (right and left portions of the tail) are orange-tan in appearance.

Life Cycle

There have been relatively few life history studies conducted on crayfish. The available life history data for Cambarus conasaugaensis is limited to the form or condition of specimens collected during certain times of the year. First-form (sexually mature) males have been collected during April, June, September and October. Egg-bearing females have been collected during April and June. Copulation usually occurs between autumn and spring. This process involves a sexually mature male crayfish grabbing a female and depositing sperm packages (spermatophores) into the seminal receptacle on the abdomen of a receptive female crayfish. Often during the spring, females secrete a sticky substance on the underside of their abdomen and pleopods in order to attach their eggs. The eggs and sperm (from the seminal receptacle) are then released upon the sticky surface and fertilization occurs. A female carrying eggs on her abdomen and legs is said to be "in berry." Embryos develop and hatch on the underside of females in 2-20 weeks, likely depending upon species and temperature. The immature hatchlings molt (shed their exoskeleton to allow growth) and remain attached to their mother. These first-stage immature crayfish look fairly similar to typical crayfish, but have disproportionately large heads and eyes. Another molting takes place in about 1-2 weeks. These second-stage immature crayfish look even more like adult crayfish. Second-stage or third-stage immature crayfish leave their mother's surface and become independent. These young crayfish continue molting and growing and are usually sexually mature by their second or third autumn. Sexually mature males and females are believed to mate between autumn and late spring and many usually die within 3 years of hatching.

Natural History

occurs while escaping predators or fighting with other crayfish. Male crayfish are particularly aggressive with one another and their claw-to-claw combat can be quite intense.

Range

Cambarus conasaugaensis is found in tributaries of the Conasauga, Coosawattee and Etowah Rivers in northern Georgia and in the Hiwassee Basin in southern Tennessee . This species has a limited range that covers only 6 counties: Dawson , Gilmer, Fannin, Pickens and Lumpkin Counties in Georgia and Polk County in Tennessee . This species is found in cool streams and seepages at elevations of more than 400 m (1312 ft).

Conservation Status

This species is listed as Uncommon and is threatened by the increased urbanization in northern Georgia . This species has a small range and could be seriously harmed by habitat destruction, pollution and habitat degradation within its home streams.

Similar Species

Accurate identification of particular species of crayfish can be quite difficult. Proper identification often relies upon subtle anatomical differences and sexual structures of first-order males. This species, however, is often the only crawfish collected from seepage areas within its limited range in Georgia .