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Species Description

Crayfish

Cambarus (Puncticambarus) scotti


Classification

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

Description

The carapace of Cambarus scotti is pinkish tan dorsally (on the top or back side). The 1 st abdominal segment is dark brown and the remaining segments of the abdomen are a light tan color. Dorsal portions of the abdomen are also decorated with distinctive L-shaped markings. The chelae (claws) are about 2.5 times as long as they are broad and are adorned with 2 rows of bright orange to red tubercles. The areola is broad and has 7-10 spots or pits in the narrowest portion. The rostrum is long and lacks both spines and tubercles (small bumps). The carapace usually measures between 24 and 48 mm (0.95-1.9 in).

Life Cycle

There have been relatively few life history studies conducted on crayfish. The available life history data for Cambarus scotti 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 March, April, May, September and October. Egg-bearing females have been collected during April, with specimens carrying between 110 and 310 eggs. The life cycle of this species is presumed to be fairly similar to the generalized crayfish life history described below. Copulation has not been observed, but probably occurs from autumn to 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 berrry" "In berry" specimens have been observed carrying between 110 and 310 eggs. The number of eggs that a female is carrying appears to vary with the size of the female. Larger females typically carry more eggs than smaller females. 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 mothe'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 spring. Many adult crayfish die within 3 years of hatching.

Natural History

ghting with other crayfish. Male crayfish are especially aggressive with one another and their claw-to-claw combat can be quite intense.

Range

This species is found within swift, rock-bottomed streams within the Chattooga River basin in Chattooga and Walker Counties in Georgia and in Cherokee County , Alabama .

Conservation Status

Cambarus scotti is uncommon or rare in Georgia . It has a small range, but populations appear to be fairly abundant when found. Possible threats to this species include water quality degradation, destruction of habitat, construction of impoundments and pollution.

Similar Species

Cambarus coosae has a similar color pattern to this crayfish species that can make identification of the species difficult. However, C. scotti is distinguished by its long rostrum that lacks both spines and tubercles.