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Species Description

Crayfish

Procambarus (Ortmannicus) epicyrtus


Classification

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

Description

The carapace of Procambarus epicyrtus is a tan-mauve color and is decorated with numerous charcoal black markings. The head is marked with a distinct stripe from the tip of the rostrum to the base of the areola region. The abdominal segments are mauve-tan and decorated anteriorly (towards the head region) with narrow charcoal bands. The chelae (claws) are long and slender. The rostrum is adorned with marginal spines or tubercles (small bumps). The areola of this species is approximately 3.5-5 times as long as it is wide. The carapace length usually measures between 25 and 52 mm (1-2 in).

Life Cycle

There have been relatively few life history studies conducted on crayfish. The available life history data for Procambarus epicyrtus 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 January, April, November and December. Very little is known about the life history of this species, but its life cycle may be fairly similar to the generalized crayfish life history described below. 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 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 Procambarus epicyrtus crayfish often hide among vegetation or leaf litter in streams and drainage ditches during the day. 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, 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, otters 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 sometimes have extensive scaring on their chelae or are 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 crayfish species is found within the Lower Ogeechee and Savannah River basins of Georgia . It has only been collected in Bryan, Bulloch, Chatham, Effingham, Jenkins and Screven counties. It prefers vegetated areas of streams and drainage ditches.

Conservation Status

This species is uncommon in Georgia , but can be fairly common when it is found within portions of its limited range. This species has a range which is restricted to parts of 6 counties in Georgia and it is threatened by expansion of the Savannah metropolitan area. Habitat destruction and water quality degradation are probably the most immediate threats to Procambarus epicyrtus.

Similar Species

Within its range along the lower Ogeechee and Savannah River basins , the combination of tannish mauve background color and charcoal markings should help distinguish this species from other crayfish. However, positive identification of crayfish can be quite difficult and often relies upon subtle anatomical features and differences which are usually best identified by trained individuals.