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Species Description

Conasauga Blue Burrower

Cambarus (Depressicambarus) cymatilis


Classification

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

Description

As its name would suggest, the Conasauga Blue Burrower is dark blue in color. The chelae are dark blue and adorned with 5-7 white tubercles (bumps) in a row. Portions of the dorsal (back or topside) surface of the tail are a pale bluish gray color. It has small eyes and a very narrow areola. The carapace length is usually less than 1.6 inches (40 mm) and total body length is usually less than 3.2 inches (80 mm). The rostrum lacks marginal spines and tubercles.

Life Cycle

There have been relatively few life history studies conducted on crayfish. The available life history data for Cambarus cymatilis 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. An egg-bearing female was collected during April and was bearing 7 eggs. The life cycle of this species is presumed to be fairly similar to the generalized crayfish life history described below. Copulation usually occurs between autumn and spring. 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. Usually 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 summer and many usually die within 3 years of hatching.

Natural History

Adult Cambarus cymatilis crayfish are found in elaborate sandy-clay burrows in areas with a high water table (a water level near the surface). This species is often found in grassy areas near houses and gardens. Crayfish are generally omnivorous scavengers, feeding upon any food source available within their habitat. Food for this species may include plant material, insects and perhaps other crayfish. 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 this species of crayfish are probably dogs, cats, frogs, turtles, raccoons and humans. Crayfish usually walk slowly using their last 4 walking legs (periopods). When frightened or in danger, however, they quickly escape by "darting" backwards. Crayfish sometimes have extensive scaring on their chelae or are missing appendages. This 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. Based upon limited observations, it has been speculated that females of this species are also very aggressive-perhaps even more aggressive than males.

Range

This species is only found in Murray County , Georgia and near Mill Creek in Bradley County, Tennessee. The Conasauga Blue Burrower is found in elaborate burrows in areas with a high water table. These burrows are often found near homes, gardens and in open, grassy areas.

Conservation Status

The Conasauga Blue Burrower is listed as Rare in Georgia due to its extremely small range within the state. The most immediate threat to this species appears to be the loss of habitat due to the development of new homes within its range.

Similar Species

Within its very limited range in Georgia , this species is usually fairly distinct. Its dark blue body and construction of elaborate burrows in yards and gardens distinguishes the Blue Burrower from other crayfish in Murray County .