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Species Description

Crayfish

Procambarus (Pennides) versutus


Classification

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

Description

The carapace of Procambarus versutus is decorated with black and cream markings on a tan background. The tail has prominent black splotches and the chelipeds (large claws) are adorned with black tubercles (small bumps). There are 2 distinctive spines on each side of the colorful carapace. The areola is broad and the carapace usually measures between 15 and 41 mm (0.6-1.6 in) in length.

Life Cycle

There have been relatively few life history studies conducted on crayfish. The available life history data for Procambarus versutus is limited to the form or condition of specimens collected during certain times of the year. First-form (sexually mature) males have been collected throughout the year. Females carrying eggs have been collected during April and June. The life cycle of this species is presumed to be fairly similar to the generalized crayfish life history described below. The exact breeding season of this species is currently unknown, but copulation likely occurs during the fall or early 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. 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.

Natural History

Adult P. versutus crayfish often hide under leaf litter in small streams. This species appears to prefer moderately swift, sand bottomed streams within its range. From dusk until dawn, or on very cloudy days, crayfish come out of hiding and search for food in streams. 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.

Range

This species is found from the Mobile River drainage in Alabama to the Chattahoochee-Apalachicola River drainage in Georgia , Florida and Alabama . Within Georgia , it is only found in Marion and Muscogee counties.

Conservation Status

Procambarus versutus is listed as rare in Georgia and is threatened by habitat destruction and pollution within its limited range in the state.

Similar Species

Although crayfish identification can be quite difficult, the combination of carapace spines, black tubercles on its claws and black carapace markings distinguishes this species from others within its range.