Cambarus (Jugicambarus) distans
The carapace of Cambarus distans is olive-tan with irregular grayish-brown markings. The dorsal (back or top side) surface of the abdomen is decorated with distinctive, paired spots. The rostrum lacks marginal spines and tubercles (small bumps). The chelae (claws) are fairly short and adorned with a row of 7-9 cream-colored tubercles. The areola region is fairly wide and has 2-4 spots or pits in the narrowest portion. The carapace often measures less than 34 mm (1.3 in) in length.
There have been relatively few life history studies conducted on crayfish. The available life history data for Cambarus distans is limited to the form or condition of specimens collected during certain times of the year. First-form (sexually mature) males have been observed in October. The life cycle of this species is presumably fairly similar to the generalized crayfish life history described below. The mating season for this species is unknown. Copulation 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. During the appropriate time(s) of year, 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. Many adult crayfish die within 3 years of hatching.
Adult Cambarus distans crayfish often hide under tree and leaf litter in cool streams. This species appears to prefer quick-flowing, clear streams. From dusk until dawn, or on very cloudy days, crayfish come out of hiding and search for food in streams. In the streams where C. distans is found, it is usually the only species of crayfish present. Crayfish are usually omnivorous scavengers, feeding upon whatever is available. Crayfish eat aquatic vegetation, detritus, small fish, aquatic insects and snails. They use their chelae (claws) on their first 3 legs to grab, crush and tear their food. This food is further cut by a number of specialized mouthparts. The main predators of crayfish are fish, frogs, turtles, wading birds, raccoons and humans. Crayfish usually walk slowly across the bottom of their stream habitat using their last 4 walking legs (periopods). When frightened or in danger, however, they quickly escape by "darting" backwards. Crayfish are sometimes found with extensive scaring on their chelae or missing appendages. This occurs while escaping predators or fighting with other crayfish. Male crayfish are especially aggressive with one another and their claw-to-claw combat can be quite intense.
Cambarus distans is found within the Kentucky , Cumberland and Tennessee River drainages of Kentucky and Tennessee . Its range extends southward to Sand Mountain in Georgia and Alabama . Within Georgia , it is only found in clear, cool streams of Sand Mountain in Dade County .
This species is listed as Rare and Imperiled in Georgia . It has a very limited range within the state and is threatened by water pollution and habitat destruction.
C. distans is distinct from other species of crayfish within Sand Mountain streams. Its combination of paired abdominal spots and irregular markings on its carapace distinguish it from other species of crayfish that are found in Dade County .